vue.js

/*!
 * Vue.js v1.0.28
 * (c) 2016 Evan You
 * Released under the MIT License.
 */
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  global.Vue = factory();
}(this, function () { 'use strict';

  function set(obj, key, val) {
    if (hasOwn(obj, key)) {
      obj[key] = val;
      return;
    }
    if (obj._isVue) {
      set(obj._data, key, val);
      return;
    }
    var ob = obj.__ob__;
    if (!ob) {
      obj[key] = val;
      return;
    }
    ob.convert(key, val);
    ob.dep.notify();
    if (ob.vms) {
      var i = ob.vms.length;
      while (i--) {
        var vm = ob.vms[i];
        vm._proxy(key);
        vm._digest();
      }
    }
    return val;
  }

  /**
   * Delete a property and trigger change if necessary.
   *
   * @param {Object} obj
   * @param {String} key
   */

  function del(obj, key) {
    if (!hasOwn(obj, key)) {
      return;
    }
    delete obj[key];
    var ob = obj.__ob__;
    if (!ob) {
      if (obj._isVue) {
        delete obj._data[key];
        obj._digest();
      }
      return;
    }
    ob.dep.notify();
    if (ob.vms) {
      var i = ob.vms.length;
      while (i--) {
        var vm = ob.vms[i];
        vm._unproxy(key);
        vm._digest();
      }
    }
  }

  var hasOwnProperty = Object.prototype.hasOwnProperty;
  /**
   * Check whether the object has the property.
   *
   * @param {Object} obj
   * @param {String} key
   * @return {Boolean}
   */

  function hasOwn(obj, key) {
    return hasOwnProperty.call(obj, key);
  }

  /**
   * Check if an expression is a literal value.
   *
   * @param {String} exp
   * @return {Boolean}
   */

  var literalValueRE$1 = /^\s?(true|false|-?[\d\.]+|'[^']*'|"[^"]*")\s?$/;

  function isLiteral(exp) {
    return literalValueRE$1.test(exp);
  }

  /**
   * Check if a string starts with $ or _
   *
   * @param {String} str
   * @return {Boolean}
   */

  function isReserved(str) {
    var c = (str + '').charCodeAt(0);
    return c === 0x24 || c === 0x5F;
  }

  /**
   * Guard text output, make sure undefined outputs
   * empty string
   *
   * @param {*} value
   * @return {String}
   */

  function _toString(value) {
    return value == null ? '' : value.toString();
  }

  /**
   * Check and convert possible numeric strings to numbers
   * before setting back to data
   *
   * @param {*} value
   * @return {*|Number}
   */

  function toNumber(value) {
    if (typeof value !== 'string') {
      return value;
    } else {
      var parsed = Number(value);
      return isNaN(parsed) ? value : parsed;
    }
  }

  /**
   * Convert string boolean literals into real booleans.
   *
   * @param {*} value
   * @return {*|Boolean}
   */

  function toBoolean(value) {
    return value === 'true' ? true : value === 'false' ? false : value;
  }

  /**
   * Strip quotes from a string
   *
   * @param {String} str
   * @return {String | false}
   */

  function stripQuotes(str) {
    var a = str.charCodeAt(0);
    var b = str.charCodeAt(str.length - 1);
    return a === b && (a === 0x22 || a === 0x27) ? str.slice(1, -1) : str;
  }

  /**
   * Camelize a hyphen-delimited string.
   *
   * @param {String} str
   * @return {String}
   */

  var camelizeRE = /-(\w)/g;

  function camelize(str) {
    return str.replace(camelizeRE, toUpper);
  }

  function toUpper(_, c) {
    return c ? c.toUpperCase() : '';
  }

  /**
   * Hyphenate a camelCase string.
   *
   * @param {String} str
   * @return {String}
   */

  var hyphenateRE = /([^-])([A-Z])/g;

  function hyphenate(str) {
    return str.replace(hyphenateRE, '$1-$2').replace(hyphenateRE, '$1-$2').toLowerCase();
  }

  /**
   * Converts hyphen/underscore/slash delimitered names into
   * camelized classNames.
   *
   * e.g. my-component => MyComponent
   *      some_else    => SomeElse
   *      some/comp    => SomeComp
   *
   * @param {String} str
   * @return {String}
   */

  var classifyRE = /(?:^|[-_\/])(\w)/g;

  function classify(str) {
    return str.replace(classifyRE, toUpper);
  }

  /**
   * Simple bind, faster than native
   *
   * @param {Function} fn
   * @param {Object} ctx
   * @return {Function}
   */

  function bind(fn, ctx) {
    return function (a) {
      var l = arguments.length;
      return l ? l > 1 ? fn.apply(ctx, arguments) : fn.call(ctx, a) : fn.call(ctx);
    };
  }

  /**
   * Convert an Array-like object to a real Array.
   *
   * @param {Array-like} list
   * @param {Number} [start] - start index
   * @return {Array}
   */

  function toArray(list, start) {
    start = start || 0;
    var i = list.length - start;
    var ret = new Array(i);
    while (i--) {
      ret[i] = list[i + start];
    }
    return ret;
  }

  /**
   * Mix properties into target object.
   *
   * @param {Object} to
   * @param {Object} from
   */

  function extend(to, from) {
    var keys = Object.keys(from);
    var i = keys.length;
    while (i--) {
      to[keys[i]] = from[keys[i]];
    }
    return to;
  }

  /**
   * Quick object check - this is primarily used to tell
   * Objects from primitive values when we know the value
   * is a JSON-compliant type.
   *
   * @param {*} obj
   * @return {Boolean}
   */

  function isObject(obj) {
    return obj !== null && typeof obj === 'object';
  }

  /**
   * Strict object type check. Only returns true
   * for plain JavaScript objects.
   *
   * @param {*} obj
   * @return {Boolean}
   */

  var toString = Object.prototype.toString;
  var OBJECT_STRING = '[object Object]';

  function isPlainObject(obj) {
    return toString.call(obj) === OBJECT_STRING;
  }

  /**
   * Array type check.
   *
   * @param {*} obj
   * @return {Boolean}
   */

  var isArray = Array.isArray;

  /**
   * Define a property.
   *
   * @param {Object} obj
   * @param {String} key
   * @param {*} val
   * @param {Boolean} [enumerable]
   */

  function def(obj, key, val, enumerable) {
    Object.defineProperty(obj, key, {
      value: val,
      enumerable: !!enumerable,
      writable: true,
      configurable: true
    });
  }

  /**
   * Debounce a function so it only gets called after the
   * input stops arriving after the given wait period.
   *
   * @param {Function} func
   * @param {Number} wait
   * @return {Function} - the debounced function
   */

  function _debounce(func, wait) {
    var timeout, args, context, timestamp, result;
    var later = function later() {
      var last = Date.now() - timestamp;
      if (last < wait && last >= 0) {
        timeout = setTimeout(later, wait - last);
      } else {
        timeout = null;
        result = func.apply(context, args);
        if (!timeout) context = args = null;
      }
    };
    return function () {
      context = this;
      args = arguments;
      timestamp = Date.now();
      if (!timeout) {
        timeout = setTimeout(later, wait);
      }
      return result;
    };
  }

  /**
   * Manual indexOf because it's slightly faster than
   * native.
   *
   * @param {Array} arr
   * @param {*} obj
   */

  function indexOf(arr, obj) {
    var i = arr.length;
    while (i--) {
      if (arr[i] === obj) return i;
    }
    return -1;
  }

  /**
   * Make a cancellable version of an async callback.
   *
   * @param {Function} fn
   * @return {Function}
   */

  function cancellable(fn) {
    var cb = function cb() {
      if (!cb.cancelled) {
        return fn.apply(this, arguments);
      }
    };
    cb.cancel = function () {
      cb.cancelled = true;
    };
    return cb;
  }

  /**
   * Check if two values are loosely equal - that is,
   * if they are plain objects, do they have the same shape?
   *
   * @param {*} a
   * @param {*} b
   * @return {Boolean}
   */

  function looseEqual(a, b) {
    /* eslint-disable eqeqeq */
    return a == b || (isObject(a) && isObject(b) ? JSON.stringify(a) === JSON.stringify(b) : false);
    /* eslint-enable eqeqeq */
  }

  var hasProto = ('__proto__' in {});

  // Browser environment sniffing
  var inBrowser = typeof window !== 'undefined' && Object.prototype.toString.call(window) !== '[object Object]';

  // detect devtools
  var devtools = inBrowser && window.__VUE_DEVTOOLS_GLOBAL_HOOK__;

  // UA sniffing for working around browser-specific quirks
  var UA = inBrowser && window.navigator.userAgent.toLowerCase();
  var isIE = UA && UA.indexOf('trident') > 0;
  var isIE9 = UA && UA.indexOf('msie 9.0') > 0;
  var isAndroid = UA && UA.indexOf('android') > 0;
  var isIOS = UA && /iphone|ipad|ipod|ios/.test(UA);

  var transitionProp = undefined;
  var transitionEndEvent = undefined;
  var animationProp = undefined;
  var animationEndEvent = undefined;

  // Transition property/event sniffing
  if (inBrowser && !isIE9) {
    var isWebkitTrans = window.ontransitionend === undefined && window.onwebkittransitionend !== undefined;
    var isWebkitAnim = window.onanimationend === undefined && window.onwebkitanimationend !== undefined;
    transitionProp = isWebkitTrans ? 'WebkitTransition' : 'transition';
    transitionEndEvent = isWebkitTrans ? 'webkitTransitionEnd' : 'transitionend';
    animationProp = isWebkitAnim ? 'WebkitAnimation' : 'animation';
    animationEndEvent = isWebkitAnim ? 'webkitAnimationEnd' : 'animationend';
  }

  /* istanbul ignore next */
  function isNative(Ctor) {
    return (/native code/.test(Ctor.toString())
    );
  }

  /**
   * Defer a task to execute it asynchronously. Ideally this
   * should be executed as a microtask, so we leverage
   * MutationObserver if it's available, and fallback to
   * setTimeout(0).
   *
   * @param {Function} cb
   * @param {Object} ctx
   */

  var nextTick = (function () {
    var callbacks = [];
    var pending = false;
    var timerFunc = undefined;

    function nextTickHandler() {
      pending = false;
      var copies = callbacks.slice(0);
      callbacks.length = 0;
      for (var i = 0; i < copies.length; i++) {
        copies[i]();
      }
    }

    // the nextTick behavior leverages the microtask queue, which can be accessed
    // via either native Promise.then or MutationObserver.
    // MutationObserver has wider support, however it is seriously bugged in
    // UIWebView in iOS >= 9.3.3 when triggered in touch event handlers. It
    // completely stops working after triggering a few times... so, if native
    // Promise is available, we will use it:
    /* istanbul ignore if */
    if (typeof Promise !== 'undefined' && isNative(Promise)) {
      var p = Promise.resolve();
      var noop = function noop() {};
      timerFunc = function () {
        p.then(nextTickHandler);
        // in problematic UIWebViews, Promise.then doesn't completely break, but
        // it can get stuck in a weird state where callbacks are pushed into the
        // microtask queue but the queue isn't being flushed, until the browser
        // needs to do some other work, e.g. handle a timer. Therefore we can
        // "force" the microtask queue to be flushed by adding an empty timer.
        if (isIOS) setTimeout(noop);
      };
    } else if (typeof MutationObserver !== 'undefined') {
      // use MutationObserver where native Promise is not available,
      // e.g. IE11, iOS7, Android 4.4
      var counter = 1;
      var observer = new MutationObserver(nextTickHandler);
      var textNode = document.createTextNode(String(counter));
      observer.observe(textNode, {
        characterData: true
      });
      timerFunc = function () {
        counter = (counter + 1) % 2;
        textNode.data = String(counter);
      };
    } else {
      // fallback to setTimeout
      /* istanbul ignore next */
      timerFunc = setTimeout;
    }

    return function (cb, ctx) {
      var func = ctx ? function () {
        cb.call(ctx);
      } : cb;
      callbacks.push(func);
      if (pending) return;
      pending = true;
      timerFunc(nextTickHandler, 0);
    };
  })();

  var Set$1 = undefined;
  /* istanbul ignore if */
  if (typeof Set !== 'undefined' && isNative(Set)) {
    // use native Set when available.
    Set$1 = Set;
  } else {
    // a non-standard Set polyfill that only works with primitive keys.
    Set$1 = function () {
      this.set = Object.create(null);
    };
    Set$1.prototype.has = function (key) {
      return this.set[key] !== undefined;
    };
    Set$1.prototype.add = function (key) {
      this.set[key] = 1;
    };
    Set$1.prototype.clear = function () {
      this.set = Object.create(null);
    };
  }

  function Cache(limit) {
    this.size = 0;
    this.limit = limit;
    this.head = this.tail = undefined;
    this._keymap = Object.create(null);
  }

  var p = Cache.prototype;

  /**
   * Put <value> into the cache associated with <key>.
   * Returns the entry which was removed to make room for
   * the new entry. Otherwise undefined is returned.
   * (i.e. if there was enough room already).
   *
   * @param {String} key
   * @param {*} value
   * @return {Entry|undefined}
   */

  p.put = function (key, value) {
    var removed;

    var entry = this.get(key, true);
    if (!entry) {
      if (this.size === this.limit) {
        removed = this.shift();
      }
      entry = {
        key: key
      };
      this._keymap[key] = entry;
      if (this.tail) {
        this.tail.newer = entry;
        entry.older = this.tail;
      } else {
        this.head = entry;
      }
      this.tail = entry;
      this.size++;
    }
    entry.value = value;

    return removed;
  };

  /**
   * Purge the least recently used (oldest) entry from the
   * cache. Returns the removed entry or undefined if the
   * cache was empty.
   */

  p.shift = function () {
    var entry = this.head;
    if (entry) {
      this.head = this.head.newer;
      this.head.older = undefined;
      entry.newer = entry.older = undefined;
      this._keymap[entry.key] = undefined;
      this.size--;
    }
    return entry;
  };

  /**
   * Get and register recent use of <key>. Returns the value
   * associated with <key> or undefined if not in cache.
   *
   * @param {String} key
   * @param {Boolean} returnEntry
   * @return {Entry|*}
   */

  p.get = function (key, returnEntry) {
    var entry = this._keymap[key];
    if (entry === undefined) return;
    if (entry === this.tail) {
      return returnEntry ? entry : entry.value;
    }
    // HEAD--------------TAIL
    //   <.older   .newer>
    //  <--- add direction --
    //   A  B  C  <D>  E
    if (entry.newer) {
      if (entry === this.head) {
        this.head = entry.newer;
      }
      entry.newer.older = entry.older; // C <-- E.
    }
    if (entry.older) {
      entry.older.newer = entry.newer; // C. --> E
    }
    entry.newer = undefined; // D --x
    entry.older = this.tail; // D. --> E
    if (this.tail) {
      this.tail.newer = entry; // E. <-- D
    }
    this.tail = entry;
    return returnEntry ? entry : entry.value;
  };

  var cache$1 = new Cache(1000);
  var reservedArgRE = /^in$|^-?\d+/;

  /**
   * Parser state
   */

  var str;
  var dir;
  var len;
  var index;
  var chr;
  var state;
  var startState = 0;
  var filterState = 1;
  var filterNameState = 2;
  var filterArgState = 3;

  var doubleChr = 0x22;
  var singleChr = 0x27;
  var pipeChr = 0x7C;
  var escapeChr = 0x5C;
  var spaceChr = 0x20;

  var expStartChr = { 0x5B: 1, 0x7B: 1, 0x28: 1 };
  var expChrPair = { 0x5B: 0x5D, 0x7B: 0x7D, 0x28: 0x29 };

  function peek() {
    return str.charCodeAt(index + 1);
  }

  function next() {
    return str.charCodeAt(++index);
  }

  function eof() {
    return index >= len;
  }

  function eatSpace() {
    while (peek() === spaceChr) {
      next();
    }
  }

  function isStringStart(chr) {
    return chr === doubleChr || chr === singleChr;
  }

  function isExpStart(chr) {
    return expStartChr[chr];
  }

  function isExpEnd(start, chr) {
    return expChrPair[start] === chr;
  }

  function parseString() {
    var stringQuote = next();
    var chr;
    while (!eof()) {
      chr = next();
      // escape char
      if (chr === escapeChr) {
        next();
      } else if (chr === stringQuote) {
        break;
      }
    }
  }

  function parseSpecialExp(chr) {
    var inExp = 0;
    var startChr = chr;

    while (!eof()) {
      chr = peek();
      if (isStringStart(chr)) {
        parseString();
        continue;
      }

      if (startChr === chr) {
        inExp++;
      }
      if (isExpEnd(startChr, chr)) {
        inExp--;
      }

      next();

      if (inExp === 0) {
        break;
      }
    }
  }

  /**
   * syntax:
   * expression | filterName  [arg  arg [| filterName arg arg]]
   */

  function parseExpression() {
    var start = index;
    while (!eof()) {
      chr = peek();
      if (isStringStart(chr)) {
        parseString();
      } else if (isExpStart(chr)) {
        parseSpecialExp(chr);
      } else if (chr === pipeChr) {
        next();
        chr = peek();
        if (chr === pipeChr) {
          next();
        } else {
          if (state === startState || state === filterArgState) {
            state = filterState;
          }
          break;
        }
      } else if (chr === spaceChr && (state === filterNameState || state === filterArgState)) {
        eatSpace();
        break;
      } else {
        if (state === filterState) {
          state = filterNameState;
        }
        next();
      }
    }

    return str.slice(start + 1, index) || null;
  }

  function parseFilterList() {
    var filters = [];
    while (!eof()) {
      filters.push(parseFilter());
    }
    return filters;
  }

  function parseFilter() {
    var filter = {};
    var args;

    state = filterState;
    filter.name = parseExpression().trim();

    state = filterArgState;
    args = parseFilterArguments();

    if (args.length) {
      filter.args = args;
    }
    return filter;
  }

  function parseFilterArguments() {
    var args = [];
    while (!eof() && state !== filterState) {
      var arg = parseExpression();
      if (!arg) {
        break;
      }
      args.push(processFilterArg(arg));
    }

    return args;
  }

  /**
   * Check if an argument is dynamic and strip quotes.
   *
   * @param {String} arg
   * @return {Object}
   */

  function processFilterArg(arg) {
    if (reservedArgRE.test(arg)) {
      return {
        value: toNumber(arg),
        dynamic: false
      };
    } else {
      var stripped = stripQuotes(arg);
      var dynamic = stripped === arg;
      return {
        value: dynamic ? arg : stripped,
        dynamic: dynamic
      };
    }
  }

  /**
   * Parse a directive value and extract the expression
   * and its filters into a descriptor.
   *
   * Example:
   *
   * "a + 1 | uppercase" will yield:
   * {
   *   expression: 'a + 1',
   *   filters: [
   *     { name: 'uppercase', args: null }
   *   ]
   * }
   *
   * @param {String} s
   * @return {Object}
   */

  function parseDirective(s) {
    var hit = cache$1.get(s);
    if (hit) {
      return hit;
    }

    // reset parser state
    str = s;
    dir = {};
    len = str.length;
    index = -1;
    chr = '';
    state = startState;

    var filters;

    if (str.indexOf('|') < 0) {
      dir.expression = str.trim();
    } else {
      dir.expression = parseExpression().trim();
      filters = parseFilterList();
      if (filters.length) {
        dir.filters = filters;
      }
    }

    cache$1.put(s, dir);
    return dir;
  }

  var directive = Object.freeze({
    parseDirective: parseDirective
  });

  var regexEscapeRE = /[-.*+?^${}()|[\]\/\\]/g;
  var cache = undefined;
  var tagRE = undefined;
  var htmlRE = undefined;
  /**
   * Escape a string so it can be used in a RegExp
   * constructor.
   *
   * @param {String} str
   */

  function escapeRegex(str) {
    return str.replace(regexEscapeRE, '\\$&');
  }

  function compileRegex() {
    var open = escapeRegex(config.delimiters[0]);
    var close = escapeRegex(config.delimiters[1]);
    var unsafeOpen = escapeRegex(config.unsafeDelimiters[0]);
    var unsafeClose = escapeRegex(config.unsafeDelimiters[1]);
    tagRE = new RegExp(unsafeOpen + '((?:.|\\n)+?)' + unsafeClose + '|' + open + '((?:.|\\n)+?)' + close, 'g');
    htmlRE = new RegExp('^' + unsafeOpen + '((?:.|\\n)+?)' + unsafeClose + '$');
    // reset cache
    cache = new Cache(1000);
  }

  /**
   * Parse a template text string into an array of tokens.
   *
   * @param {String} text
   * @return {Array<Object> | null}
   *               - {String} type
   *               - {String} value
   *               - {Boolean} [html]
   *               - {Boolean} [oneTime]
   */

  function parseText(text) {
    if (!cache) {
      compileRegex();
    }
    var hit = cache.get(text);
    if (hit) {
      return hit;
    }
    if (!tagRE.test(text)) {
      return null;
    }
    var tokens = [];
    var lastIndex = tagRE.lastIndex = 0;
    var match, index, html, value, first, oneTime;
    /* eslint-disable no-cond-assign */
    while (match = tagRE.exec(text)) {
      /* eslint-enable no-cond-assign */
      index = match.index;
      // push text token
      if (index > lastIndex) {
        tokens.push({
          value: text.slice(lastIndex, index)
        });
      }
      // tag token
      html = htmlRE.test(match[0]);
      value = html ? match[1] : match[2];
      first = value.charCodeAt(0);
      oneTime = first === 42; // *
      value = oneTime ? value.slice(1) : value;
      tokens.push({
        tag: true,
        value: value.trim(),
        html: html,
        oneTime: oneTime
      });
      lastIndex = index + match[0].length;
    }
    if (lastIndex < text.length) {
      tokens.push({
        value: text.slice(lastIndex)
      });
    }
    cache.put(text, tokens);
    return tokens;
  }

  /**
   * Format a list of tokens into an expression.
   * e.g. tokens parsed from 'a {{b}} c' can be serialized
   * into one single expression as '"a " + b + " c"'.
   *
   * @param {Array} tokens
   * @param {Vue} [vm]
   * @return {String}
   */

  function tokensToExp(tokens, vm) {
    if (tokens.length > 1) {
      return tokens.map(function (token) {
        return formatToken(token, vm);
      }).join('+');
    } else {
      return formatToken(tokens[0], vm, true);
    }
  }

  /**
   * Format a single token.
   *
   * @param {Object} token
   * @param {Vue} [vm]
   * @param {Boolean} [single]
   * @return {String}
   */

  function formatToken(token, vm, single) {
    return token.tag ? token.oneTime && vm ? '"' + vm.$eval(token.value) + '"' : inlineFilters(token.value, single) : '"' + token.value + '"';
  }

  /**
   * For an attribute with multiple interpolation tags,
   * e.g. attr="some-{{thing | filter}}", in order to combine
   * the whole thing into a single watchable expression, we
   * have to inline those filters. This function does exactly
   * that. This is a bit hacky but it avoids heavy changes
   * to directive parser and watcher mechanism.
   *
   * @param {String} exp
   * @param {Boolean} single
   * @return {String}
   */

  var filterRE$1 = /[^|]\|[^|]/;
  function inlineFilters(exp, single) {
    if (!filterRE$1.test(exp)) {
      return single ? exp : '(' + exp + ')';
    } else {
      var dir = parseDirective(exp);
      if (!dir.filters) {
        return '(' + exp + ')';
      } else {
        return 'this._applyFilters(' + dir.expression + // value
        ',null,' + // oldValue (null for read)
        JSON.stringify(dir.filters) + // filter descriptors
        ',false)'; // write?
      }
    }
  }

  var text = Object.freeze({
    compileRegex: compileRegex,
    parseText: parseText,
    tokensToExp: tokensToExp
  });

  var delimiters = ['{{', '}}'];
  var unsafeDelimiters = ['{{{', '}}}'];

  var config = Object.defineProperties({

    /**
     * Whether to print debug messages.
     * Also enables stack trace for warnings.
     *
     * @type {Boolean}
     */

    debug: false,

    /**
     * Whether to suppress warnings.
     *
     * @type {Boolean}
     */

    silent: false,

    /**
     * Whether to use async rendering.
     */

    async: true,

    /**
     * Whether to warn against errors caught when evaluating
     * expressions.
     */

    warnExpressionErrors: true,

    /**
     * Whether to allow devtools inspection.
     * Disabled by default in production builds.
     */

    devtools: 'development' !== 'production',

    /**
     * Internal flag to indicate the delimiters have been
     * changed.
     *
     * @type {Boolean}
     */

    _delimitersChanged: true,

    /**
     * List of asset types that a component can own.
     *
     * @type {Array}
     */

    _assetTypes: ['component', 'directive', 'elementDirective', 'filter', 'transition', 'partial'],

    /**
     * prop binding modes
     */

    _propBindingModes: {
      ONE_WAY: 0,
      TWO_WAY: 1,
      ONE_TIME: 2
    },

    /**
     * Max circular updates allowed in a batcher flush cycle.
     */

    _maxUpdateCount: 100

  }, {
    delimiters: { /**
                   * Interpolation delimiters. Changing these would trigger
                   * the text parser to re-compile the regular expressions.
                   *
                   * @type {Array<String>}
                   */

      get: function get() {
        return delimiters;
      },
      set: function set(val) {
        delimiters = val;
        compileRegex();
      },
      configurable: true,
      enumerable: true
    },
    unsafeDelimiters: {
      get: function get() {
        return unsafeDelimiters;
      },
      set: function set(val) {
        unsafeDelimiters = val;
        compileRegex();
      },
      configurable: true,
      enumerable: true
    }
  });

  var warn = undefined;
  var formatComponentName = undefined;

  if ('development' !== 'production') {
    (function () {
      var hasConsole = typeof console !== 'undefined';

      warn = function (msg, vm) {
        if (hasConsole && !config.silent) {
          console.error('[Vue warn]: ' + msg + (vm ? formatComponentName(vm) : ''));
        }
      };

      formatComponentName = function (vm) {
        var name = vm._isVue ? vm.$options.name : vm.name;
        return name ? ' (found in component: <' + hyphenate(name) + '>)' : '';
      };
    })();
  }

  /**
   * Query an element selector if it's not an element already.
   *
   * @param {String|Element} el
   * @return {Element}
   */

  function query(el) {
    if (typeof el === 'string') {
      var selector = el;
      el = document.querySelector(el);
      if (!el) {
        'development' !== 'production' && warn('Cannot find element: ' + selector);
      }
    }
    return el;
  }

  /**
   * Check if a node is in the document.
   * Note: document.documentElement.contains should work here
   * but always returns false for comment nodes in phantomjs,
   * making unit tests difficult. This is fixed by doing the
   * contains() check on the node's parentNode instead of
   * the node itself.
   *
   * @param {Node} node
   * @return {Boolean}
   */

  function inDoc(node) {
    if (!node) return false;
    var doc = node.ownerDocument.documentElement;
    var parent = node.parentNode;
    return doc === node || doc === parent || !!(parent && parent.nodeType === 1 && doc.contains(parent));
  }

  /**
   * Get and remove an attribute from a node.
   *
   * @param {Node} node
   * @param {String} _attr
   */

  function getAttr(node, _attr) {
    var val = node.getAttribute(_attr);
    if (val !== null) {
      node.removeAttribute(_attr);
    }
    return val;
  }

  /**
   * Get an attribute with colon or v-bind: prefix.
   *
   * @param {Node} node
   * @param {String} name
   * @return {String|null}
   */

  function getBindAttr(node, name) {
    var val = getAttr(node, ':' + name);
    if (val === null) {
      val = getAttr(node, 'v-bind:' + name);
    }
    return val;
  }

  /**
   * Check the presence of a bind attribute.
   *
   * @param {Node} node
   * @param {String} name
   * @return {Boolean}
   */

  function hasBindAttr(node, name) {
    return node.hasAttribute(name) || node.hasAttribute(':' + name) || node.hasAttribute('v-bind:' + name);
  }

  /**
   * Insert el before target
   *
   * @param {Element} el
   * @param {Element} target
   */

  function before(el, target) {
    target.parentNode.insertBefore(el, target);
  }

  /**
   * Insert el after target
   *
   * @param {Element} el
   * @param {Element} target
   */

  function after(el, target) {
    if (target.nextSibling) {
      before(el, target.nextSibling);
    } else {
      target.parentNode.appendChild(el);
    }
  }

  /**
   * Remove el from DOM
   *
   * @param {Element} el
   */

  function remove(el) {
    el.parentNode.removeChild(el);
  }

  /**
   * Prepend el to target
   *
   * @param {Element} el
   * @param {Element} target
   */

  function prepend(el, target) {
    if (target.firstChild) {
      before(el, target.firstChild);
    } else {
      target.appendChild(el);
    }
  }

  /**
   * Replace target with el
   *
   * @param {Element} target
   * @param {Element} el
   */

  function replace(target, el) {
    var parent = target.parentNode;
    if (parent) {
      parent.replaceChild(el, target);
    }
  }

  /**
   * Add event listener shorthand.
   *
   * @param {Element} el
   * @param {String} event
   * @param {Function} cb
   * @param {Boolean} [useCapture]
   */

  function on(el, event, cb, useCapture) {
    el.addEventListener(event, cb, useCapture);
  }

  /**
   * Remove event listener shorthand.
   *
   * @param {Element} el
   * @param {String} event
   * @param {Function} cb
   */

  function off(el, event, cb) {
    el.removeEventListener(event, cb);
  }

  /**
   * For IE9 compat: when both class and :class are present
   * getAttribute('class') returns wrong value...
   *
   * @param {Element} el
   * @return {String}
   */

  function getClass(el) {
    var classname = el.className;
    if (typeof classname === 'object') {
      classname = classname.baseVal || '';
    }
    return classname;
  }

  /**
   * In IE9, setAttribute('class') will result in empty class
   * if the element also has the :class attribute; However in
   * PhantomJS, setting `className` does not work on SVG elements...
   * So we have to do a conditional check here.
   *
   * @param {Element} el
   * @param {String} cls
   */

  function setClass(el, cls) {
    /* istanbul ignore if */
    if (isIE9 && !/svg$/.test(el.namespaceURI)) {
      el.className = cls;
    } else {
      el.setAttribute('class', cls);
    }
  }

  /**
   * Add class with compatibility for IE & SVG
   *
   * @param {Element} el
   * @param {String} cls
   */

  function addClass(el, cls) {
    if (el.classList) {
      el.classList.add(cls);
    } else {
      var cur = ' ' + getClass(el) + ' ';
      if (cur.indexOf(' ' + cls + ' ') < 0) {
        setClass(el, (cur + cls).trim());
      }
    }
  }

  /**
   * Remove class with compatibility for IE & SVG
   *
   * @param {Element} el
   * @param {String} cls
   */

  function removeClass(el, cls) {
    if (el.classList) {
      el.classList.remove(cls);
    } else {
      var cur = ' ' + getClass(el) + ' ';
      var tar = ' ' + cls + ' ';
      while (cur.indexOf(tar) >= 0) {
        cur = cur.replace(tar, ' ');
      }
      setClass(el, cur.trim());
    }
    if (!el.className) {
      el.removeAttribute('class');
    }
  }

  /**
   * Extract raw content inside an element into a temporary
   * container div
   *
   * @param {Element} el
   * @param {Boolean} asFragment
   * @return {Element|DocumentFragment}
   */

  function extractContent(el, asFragment) {
    var child;
    var rawContent;
    /* istanbul ignore if */
    if (isTemplate(el) && isFragment(el.content)) {
      el = el.content;
    }
    if (el.hasChildNodes()) {
      trimNode(el);
      rawContent = asFragment ? document.createDocumentFragment() : document.createElement('div');
      /* eslint-disable no-cond-assign */
      while (child = el.firstChild) {
        /* eslint-enable no-cond-assign */
        rawContent.appendChild(child);
      }
    }
    return rawContent;
  }

  /**
   * Trim possible empty head/tail text and comment
   * nodes inside a parent.
   *
   * @param {Node} node
   */

  function trimNode(node) {
    var child;
    /* eslint-disable no-sequences */
    while ((child = node.firstChild, isTrimmable(child))) {
      node.removeChild(child);
    }
    while ((child = node.lastChild, isTrimmable(child))) {
      node.removeChild(child);
    }
    /* eslint-enable no-sequences */
  }

  function isTrimmable(node) {
    return node && (node.nodeType === 3 && !node.data.trim() || node.nodeType === 8);
  }

  /**
   * Check if an element is a template tag.
   * Note if the template appears inside an SVG its tagName
   * will be in lowercase.
   *
   * @param {Element} el
   */

  function isTemplate(el) {
    return el.tagName && el.tagName.toLowerCase() === 'template';
  }

  /**
   * Create an "anchor" for performing dom insertion/removals.
   * This is used in a number of scenarios:
   * - fragment instance
   * - v-html
   * - v-if
   * - v-for
   * - component
   *
   * @param {String} content
   * @param {Boolean} persist - IE trashes empty textNodes on
   *                            cloneNode(true), so in certain
   *                            cases the anchor needs to be
   *                            non-empty to be persisted in
   *                            templates.
   * @return {Comment|Text}
   */

  function createAnchor(content, persist) {
    var anchor = config.debug ? document.createComment(content) : document.createTextNode(persist ? ' ' : '');
    anchor.__v_anchor = true;
    return anchor;
  }

  /**
   * Find a component ref attribute that starts with $.
   *
   * @param {Element} node
   * @return {String|undefined}
   */

  var refRE = /^v-ref:/;

  function findRef(node) {
    if (node.hasAttributes()) {
      var attrs = node.attributes;
      for (var i = 0, l = attrs.length; i < l; i++) {
        var name = attrs[i].name;
        if (refRE.test(name)) {
          return camelize(name.replace(refRE, ''));
        }
      }
    }
  }

  /**
   * Map a function to a range of nodes .
   *
   * @param {Node} node
   * @param {Node} end
   * @param {Function} op
   */

  function mapNodeRange(node, end, op) {
    var next;
    while (node !== end) {
      next = node.nextSibling;
      op(node);
      node = next;
    }
    op(end);
  }

  /**
   * Remove a range of nodes with transition, store
   * the nodes in a fragment with correct ordering,
   * and call callback when done.
   *
   * @param {Node} start
   * @param {Node} end
   * @param {Vue} vm
   * @param {DocumentFragment} frag
   * @param {Function} cb
   */

  function removeNodeRange(start, end, vm, frag, cb) {
    var done = false;
    var removed = 0;
    var nodes = [];
    mapNodeRange(start, end, function (node) {
      if (node === end) done = true;
      nodes.push(node);
      removeWithTransition(node, vm, onRemoved);
    });
    function onRemoved() {
      removed++;
      if (done && removed >= nodes.length) {
        for (var i = 0; i < nodes.length; i++) {
          frag.appendChild(nodes[i]);
        }
        cb && cb();
      }
    }
  }

  /**
   * Check if a node is a DocumentFragment.
   *
   * @param {Node} node
   * @return {Boolean}
   */

  function isFragment(node) {
    return node && node.nodeType === 11;
  }

  /**
   * Get outerHTML of elements, taking care
   * of SVG elements in IE as well.
   *
   * @param {Element} el
   * @return {String}
   */

  function getOuterHTML(el) {
    if (el.outerHTML) {
      return el.outerHTML;
    } else {
      var container = document.createElement('div');
      container.appendChild(el.cloneNode(true));
      return container.innerHTML;
    }
  }

  var uid = 0;

  function initMixin (Vue) {
    /**
     * The main init sequence. This is called for every
     * instance, including ones that are created from extended
     * constructors.
     *
     * @param {Object} options - this options object should be
     *                           the result of merging class
     *                           options and the options passed
     *                           in to the constructor.
     */

    Vue.prototype._init = function (options) {
      options = options || {};

      this.$el = null;
      this.$parent = options.parent;
      this.$root = this.$parent ? this.$parent.$root : this;
      this.$children = [];
      this.$refs = {}; // child vm references
      this.$els = {}; // element references
      this._watchers = []; // all watchers as an array
      this._directives = []; // all directives

      // a uid
      this._uid = uid++;

      // a flag to avoid this being observed
      this._isVue = true;

      // events bookkeeping
      this._events = {}; // registered callbacks
      this._eventsCount = {}; // for $broadcast optimization

      // fragment instance properties
      this._isFragment = false;
      this._fragment = // @type {DocumentFragment}
      this._fragmentStart = // @type {Text|Comment}
      this._fragmentEnd = null; // @type {Text|Comment}

      // lifecycle state
      this._isCompiled = this._isDestroyed = this._isReady = this._isAttached = this._isBeingDestroyed = this._vForRemoving = false;
      this._unlinkFn = null;

      // context:
      // if this is a transcluded component, context
      // will be the common parent vm of this instance
      // and its host.
      this._context = options._context || this.$parent;

      // scope:
      // if this is inside an inline v-for, the scope
      // will be the intermediate scope created for this
      // repeat fragment. this is used for linking props
      // and container directives.
      this._scope = options._scope;

      // fragment:
      // if this instance is compiled inside a Fragment, it
      // needs to register itself as a child of that fragment
      // for attach/detach to work properly.
      this._frag = options._frag;
      if (this._frag) {
        this._frag.children.push(this);
      }

      // push self into parent / transclusion host
      if (this.$parent) {
        this.$parent.$children.push(this);
      }

      // merge options.
      options = this.$options = mergeOptions(this.constructor.options, options, this);

      // set ref
      this._updateRef();

      // initialize data as empty object.
      // it will be filled up in _initData().
      this._data = {};

      // call init hook
      this._callHook('init');

      // initialize data observation and scope inheritance.
      this._initState();

      // setup event system and option events.
      this._initEvents();

      // call created hook
      this._callHook('created');

      // if `el` option is passed, start compilation.
      if (options.el) {
        this.$mount(options.el);
      }
    };
  }

  var uid$2 = 0;

  /**
   * A dep is an observable that can have multiple
   * directives subscribing to it.
   *
   * @constructor
   */
  function Dep() {
    this.id = uid$2++;
    this.subs = [];
  }

  // the current target watcher being evaluated.
  // this is globally unique because there could be only one
  // watcher being evaluated at any time.
  Dep.target = null;

  /**
   * Add a directive subscriber.
   *
   * @param {Directive} sub
   */

  Dep.prototype.addSub = function (sub) {
    this.subs.push(sub);
  };

  /**
   * Remove a directive subscriber.
   *
   * @param {Directive} sub
   */

  Dep.prototype.removeSub = function (sub) {
    this.subs.$remove(sub);
  };

  /**
   * Add self as a dependency to the target watcher.
   */

  Dep.prototype.depend = function () {
    Dep.target.addDep(this);
  };

  /**
   * Notify all subscribers of a new value.
   */

  Dep.prototype.notify = function () {
    // stablize the subscriber list first
    var subs = toArray(this.subs);
    for (var i = 0, l = subs.length; i < l; i++) {
      subs[i].update();
    }
  };

  var pathCache = new Cache(1000);

  // actions
  var APPEND = 0;
  var PUSH = 1;
  var INC_SUB_PATH_DEPTH = 2;
  var PUSH_SUB_PATH = 3;

  // states
  var BEFORE_PATH = 0;
  var IN_PATH = 1;
  var BEFORE_IDENT = 2;
  var IN_IDENT = 3;
  var IN_SUB_PATH = 4;
  var IN_SINGLE_QUOTE = 5;
  var IN_DOUBLE_QUOTE = 6;
  var AFTER_PATH = 7;
  var ERROR = 8;

  var pathStateMachine = [];

  pathStateMachine[BEFORE_PATH] = {
    'ws': [BEFORE_PATH],
    'ident': [IN_IDENT, APPEND],
    '[': [IN_SUB_PATH],
    'eof': [AFTER_PATH]
  };

  pathStateMachine[IN_PATH] = {
    'ws': [IN_PATH],
    '.': [BEFORE_IDENT],
    '[': [IN_SUB_PATH],
    'eof': [AFTER_PATH]
  };

  pathStateMachine[BEFORE_IDENT] = {
    'ws': [BEFORE_IDENT],
    'ident': [IN_IDENT, APPEND]
  };

  pathStateMachine[IN_IDENT] = {
    'ident': [IN_IDENT, APPEND],
    '0': [IN_IDENT, APPEND],
    'number': [IN_IDENT, APPEND],
    'ws': [IN_PATH, PUSH],
    '.': [BEFORE_IDENT, PUSH],
    '[': [IN_SUB_PATH, PUSH],
    'eof': [AFTER_PATH, PUSH]
  };

  pathStateMachine[IN_SUB_PATH] = {
    "'": [IN_SINGLE_QUOTE, APPEND],
    '"': [IN_DOUBLE_QUOTE, APPEND],
    '[': [IN_SUB_PATH, INC_SUB_PATH_DEPTH],
    ']': [IN_PATH, PUSH_SUB_PATH],
    'eof': ERROR,
    'else': [IN_SUB_PATH, APPEND]
  };

  pathStateMachine[IN_SINGLE_QUOTE] = {
    "'": [IN_SUB_PATH, APPEND],
    'eof': ERROR,
    'else': [IN_SINGLE_QUOTE, APPEND]
  };

  pathStateMachine[IN_DOUBLE_QUOTE] = {
    '"': [IN_SUB_PATH, APPEND],
    'eof': ERROR,
    'else': [IN_DOUBLE_QUOTE, APPEND]
  };

  /**
   * Determine the type of a character in a keypath.
   *
   * @param {Char} ch
   * @return {String} type
   */

  function getPathCharType(ch) {
    if (ch === undefined) {
      return 'eof';
    }

    var code = ch.charCodeAt(0);

    switch (code) {
      case 0x5B: // [
      case 0x5D: // ]
      case 0x2E: // .
      case 0x22: // "
      case 0x27: // '
      case 0x30:
        // 0
        return ch;

      case 0x5F: // _
      case 0x24:
        // $
        return 'ident';

      case 0x20: // Space
      case 0x09: // Tab
      case 0x0A: // Newline
      case 0x0D: // Return
      case 0xA0: // No-break space
      case 0xFEFF: // Byte Order Mark
      case 0x2028: // Line Separator
      case 0x2029:
        // Paragraph Separator
        return 'ws';
    }

    // a-z, A-Z
    if (code >= 0x61 && code <= 0x7A || code >= 0x41 && code <= 0x5A) {
      return 'ident';
    }

    // 1-9
    if (code >= 0x31 && code <= 0x39) {
      return 'number';
    }

    return 'else';
  }

  /**
   * Format a subPath, return its plain form if it is
   * a literal string or number. Otherwise prepend the
   * dynamic indicator (*).
   *
   * @param {String} path
   * @return {String}
   */

  function formatSubPath(path) {
    var trimmed = path.trim();
    // invalid leading 0
    if (path.charAt(0) === '0' && isNaN(path)) {
      return false;
    }
    return isLiteral(trimmed) ? stripQuotes(trimmed) : '*' + trimmed;
  }

  /**
   * Parse a string path into an array of segments
   *
   * @param {String} path
   * @return {Array|undefined}
   */

  function parse(path) {
    var keys = [];
    var index = -1;
    var mode = BEFORE_PATH;
    var subPathDepth = 0;
    var c, newChar, key, type, transition, action, typeMap;

    var actions = [];

    actions[PUSH] = function () {
      if (key !== undefined) {
        keys.push(key);
        key = undefined;
      }
    };

    actions[APPEND] = function () {
      if (key === undefined) {
        key = newChar;
      } else {
        key += newChar;
      }
    };

    actions[INC_SUB_PATH_DEPTH] = function () {
      actions[APPEND]();
      subPathDepth++;
    };

    actions[PUSH_SUB_PATH] = function () {
      if (subPathDepth > 0) {
        subPathDepth--;
        mode = IN_SUB_PATH;
        actions[APPEND]();
      } else {
        subPathDepth = 0;
        key = formatSubPath(key);
        if (key === false) {
          return false;
        } else {
          actions[PUSH]();
        }
      }
    };

    function maybeUnescapeQuote() {
      var nextChar = path[index + 1];
      if (mode === IN_SINGLE_QUOTE && nextChar === "'" || mode === IN_DOUBLE_QUOTE && nextChar === '"') {
        index++;
        newChar = '\\' + nextChar;
        actions[APPEND]();
        return true;
      }
    }

    while (mode != null) {
      index++;
      c = path[index];

      if (c === '\\' && maybeUnescapeQuote()) {
        continue;
      }

      type = getPathCharType(c);
      typeMap = pathStateMachine[mode];
      transition = typeMap[type] || typeMap['else'] || ERROR;

      if (transition === ERROR) {
        return; // parse error
      }

      mode = transition[0];
      action = actions[transition[1]];
      if (action) {
        newChar = transition[2];
        newChar = newChar === undefined ? c : newChar;
        if (action() === false) {
          return;
        }
      }

      if (mode === AFTER_PATH) {
        keys.raw = path;
        return keys;
      }
    }
  }

  /**
   * External parse that check for a cache hit first
   *
   * @param {String} path
   * @return {Array|undefined}
   */

  function parsePath(path) {
    var hit = pathCache.get(path);
    if (!hit) {
      hit = parse(path);
      if (hit) {
        pathCache.put(path, hit);
      }
    }
    return hit;
  }

  /**
   * Get from an object from a path string
   *
   * @param {Object} obj
   * @param {String} path
   */

  function getPath(obj, path) {
    return parseExpression$1(path).get(obj);
  }

  /**
   * Warn against setting non-existent root path on a vm.
   */

  var warnNonExistent;
  if ('development' !== 'production') {
    warnNonExistent = function (path, vm) {
      warn('You are setting a non-existent path "' + path.raw + '" ' + 'on a vm instance. Consider pre-initializing the property ' + 'with the "data" option for more reliable reactivity ' + 'and better performance.', vm);
    };
  }

  /**
   * Set on an object from a path
   *
   * @param {Object} obj
   * @param {String | Array} path
   * @param {*} val
   */

  function setPath(obj, path, val) {
    var original = obj;
    if (typeof path === 'string') {
      path = parse(path);
    }
    if (!path || !isObject(obj)) {
      return false;
    }
    var last, key;
    for (var i = 0, l = path.length; i < l; i++) {
      last = obj;
      key = path[i];
      if (key.charAt(0) === '*') {
        key = parseExpression$1(key.slice(1)).get.call(original, original);
      }
      if (i < l - 1) {
        obj = obj[key];
        if (!isObject(obj)) {
          obj = {};
          if ('development' !== 'production' && last._isVue) {
            warnNonExistent(path, last);
          }
          set(last, key, obj);
        }
      } else {
        if (isArray(obj)) {
          obj.$set(key, val);
        } else if (key in obj) {
          obj[key] = val;
        } else {
          if ('development' !== 'production' && obj._isVue) {
            warnNonExistent(path, obj);
          }
          set(obj, key, val);
        }
      }
    }
    return true;
  }

  var path = Object.freeze({
    parsePath: parsePath,
    getPath: getPath,
    setPath: setPath
  });

  var expressionCache = new Cache(1000);

  var allowedKeywords = 'Math,Date,this,true,false,null,undefined,Infinity,NaN,' + 'isNaN,isFinite,decodeURI,decodeURIComponent,encodeURI,' + 'encodeURIComponent,parseInt,parseFloat';
  var allowedKeywordsRE = new RegExp('^(' + allowedKeywords.replace(/,/g, '\\b|') + '\\b)');

  // keywords that don't make sense inside expressions
  var improperKeywords = 'break,case,class,catch,const,continue,debugger,default,' + 'delete,do,else,export,extends,finally,for,function,if,' + 'import,in,instanceof,let,return,super,switch,throw,try,' + 'var,while,with,yield,enum,await,implements,package,' + 'protected,static,interface,private,public';
  var improperKeywordsRE = new RegExp('^(' + improperKeywords.replace(/,/g, '\\b|') + '\\b)');

  var wsRE = /\s/g;
  var newlineRE = /\n/g;
  var saveRE = /[\{,]\s*[\w\$_]+\s*:|('(?:[^'\\]|\\.)*'|"(?:[^"\\]|\\.)*"|`(?:[^`\\]|\\.)*\$\{|\}(?:[^`\\"']|\\.)*`|`(?:[^`\\]|\\.)*`)|new |typeof |void /g;
  var restoreRE = /"(\d+)"/g;
  var pathTestRE = /^[A-Za-z_$][\w$]*(?:\.[A-Za-z_$][\w$]*|\['.*?'\]|\[".*?"\]|\[\d+\]|\[[A-Za-z_$][\w$]*\])*$/;
  var identRE = /[^\w$\.](?:[A-Za-z_$][\w$]*)/g;
  var literalValueRE = /^(?:true|false|null|undefined|Infinity|NaN)$/;

  function noop() {}

  /**
   * Save / Rewrite / Restore
   *
   * When rewriting paths found in an expression, it is
   * possible for the same letter sequences to be found in
   * strings and Object literal property keys. Therefore we
   * remove and store these parts in a temporary array, and
   * restore them after the path rewrite.
   */

  var saved = [];

  /**
   * Save replacer
   *
   * The save regex can match two possible cases:
   * 1. An opening object literal
   * 2. A string
   * If matched as a plain string, we need to escape its
   * newlines, since the string needs to be preserved when
   * generating the function body.
   *
   * @param {String} str
   * @param {String} isString - str if matched as a string
   * @return {String} - placeholder with index
   */

  function save(str, isString) {
    var i = saved.length;
    saved[i] = isString ? str.replace(newlineRE, '\\n') : str;
    return '"' + i + '"';
  }

  /**
   * Path rewrite replacer
   *
   * @param {String} raw
   * @return {String}
   */

  function rewrite(raw) {
    var c = raw.charAt(0);
    var path = raw.slice(1);
    if (allowedKeywordsRE.test(path)) {
      return raw;
    } else {
      path = path.indexOf('"') > -1 ? path.replace(restoreRE, restore) : path;
      return c + 'scope.' + path;
    }
  }

  /**
   * Restore replacer
   *
   * @param {String} str
   * @param {String} i - matched save index
   * @return {String}
   */

  function restore(str, i) {
    return saved[i];
  }

  /**
   * Rewrite an expression, prefixing all path accessors with
   * `scope.` and generate getter/setter functions.
   *
   * @param {String} exp
   * @return {Function}
   */

  function compileGetter(exp) {
    if (improperKeywordsRE.test(exp)) {
      'development' !== 'production' && warn('Avoid using reserved keywords in expression: ' + exp);
    }
    // reset state
    saved.length = 0;
    // save strings and object literal keys
    var body = exp.replace(saveRE, save).replace(wsRE, '');
    // rewrite all paths
    // pad 1 space here because the regex matches 1 extra char
    body = (' ' + body).replace(identRE, rewrite).replace(restoreRE, restore);
    return makeGetterFn(body);
  }

  /**
   * Build a getter function. Requires eval.
   *
   * We isolate the try/catch so it doesn't affect the
   * optimization of the parse function when it is not called.
   *
   * @param {String} body
   * @return {Function|undefined}
   */

  function makeGetterFn(body) {
    try {
      /* eslint-disable no-new-func */
      return new Function('scope', 'return ' + body + ';');
      /* eslint-enable no-new-func */
    } catch (e) {
      if ('development' !== 'production') {
        /* istanbul ignore if */
        if (e.toString().match(/unsafe-eval|CSP/)) {
          warn('It seems you are using the default build of Vue.js in an environment ' + 'with Content Security Policy that prohibits unsafe-eval. ' + 'Use the CSP-compliant build instead: ' + 'http://vuejs.org/guide/installation.html#CSP-compliant-build');
        } else {
          warn('Invalid expression. ' + 'Generated function body: ' + body);
        }
      }
      return noop;
    }
  }

  /**
   * Compile a setter function for the expression.
   *
   * @param {String} exp
   * @return {Function|undefined}
   */

  function compileSetter(exp) {
    var path = parsePath(exp);
    if (path) {
      return function (scope, val) {
        setPath(scope, path, val);
      };
    } else {
      'development' !== 'production' && warn('Invalid setter expression: ' + exp);
    }
  }

  /**
   * Parse an expression into re-written getter/setters.
   *
   * @param {String} exp
   * @param {Boolean} needSet
   * @return {Function}
   */

  function parseExpression$1(exp, needSet) {
    exp = exp.trim();
    // try cache
    var hit = expressionCache.get(exp);
    if (hit) {
      if (needSet && !hit.set) {
        hit.set = compileSetter(hit.exp);
      }
      return hit;
    }
    var res = { exp: exp };
    res.get = isSimplePath(exp) && exp.indexOf('[') < 0
    // optimized super simple getter
    ? makeGetterFn('scope.' + exp)
    // dynamic getter
    : compileGetter(exp);
    if (needSet) {
      res.set = compileSetter(exp);
    }
    expressionCache.put(exp, res);
    return res;
  }

  /**
   * Check if an expression is a simple path.
   *
   * @param {String} exp
   * @return {Boolean}
   */

  function isSimplePath(exp) {
    return pathTestRE.test(exp) &&
    // don't treat literal values as paths
    !literalValueRE.test(exp) &&
    // Math constants e.g. Math.PI, Math.E etc.
    exp.slice(0, 5) !== 'Math.';
  }

  var expression = Object.freeze({
    parseExpression: parseExpression$1,
    isSimplePath: isSimplePath
  });

  // we have two separate queues: one for directive updates
  // and one for user watcher registered via $watch().
  // we want to guarantee directive updates to be called
  // before user watchers so that when user watchers are
  // triggered, the DOM would have already been in updated
  // state.

  var queue = [];
  var userQueue = [];
  var has = {};
  var circular = {};
  var waiting = false;

  /**
   * Reset the batcher's state.
   */

  function resetBatcherState() {
    queue.length = 0;
    userQueue.length = 0;
    has = {};
    circular = {};
    waiting = false;
  }

  /**
   * Flush both queues and run the watchers.
   */

  function flushBatcherQueue() {
    var _again = true;

    _function: while (_again) {
      _again = false;

      runBatcherQueue(queue);
      runBatcherQueue(userQueue);
      // user watchers triggered more watchers,
      // keep flushing until it depletes
      if (queue.length) {
        _again = true;
        continue _function;
      }
      // dev tool hook
      /* istanbul ignore if */
      if (devtools && config.devtools) {
        devtools.emit('flush');
      }
      resetBatcherState();
    }
  }

  /**
   * Run the watchers in a single queue.
   *
   * @param {Array} queue
   */

  function runBatcherQueue(queue) {
    // do not cache length because more watchers might be pushed
    // as we run existing watchers
    for (var i = 0; i < queue.length; i++) {
      var watcher = queue[i];
      var id = watcher.id;
      has[id] = null;
      watcher.run();
      // in dev build, check and stop circular updates.
      if ('development' !== 'production' && has[id] != null) {
        circular[id] = (circular[id] || 0) + 1;
        if (circular[id] > config._maxUpdateCount) {
          warn('You may have an infinite update loop for watcher ' + 'with expression "' + watcher.expression + '"', watcher.vm);
          break;
        }
      }
    }
    queue.length = 0;
  }

  /**
   * Push a watcher into the watcher queue.
   * Jobs with duplicate IDs will be skipped unless it's
   * pushed when the queue is being flushed.
   *
   * @param {Watcher} watcher
   *   properties:
   *   - {Number} id
   *   - {Function} run
   */

  function pushWatcher(watcher) {
    var id = watcher.id;
    if (has[id] == null) {
      // push watcher into appropriate queue
      var q = watcher.user ? userQueue : queue;
      has[id] = q.length;
      q.push(watcher);
      // queue the flush
      if (!waiting) {
        waiting = true;
        nextTick(flushBatcherQueue);
      }
    }
  }

  var uid$1 = 0;

  /**
   * A watcher parses an expression, collects dependencies,
   * and fires callback when the expression value changes.
   * This is used for both the $watch() api and directives.
   *
   * @param {Vue} vm
   * @param {String|Function} expOrFn
   * @param {Function} cb
   * @param {Object} options
   *                 - {Array} filters
   *                 - {Boolean} twoWay
   *                 - {Boolean} deep
   *                 - {Boolean} user
   *                 - {Boolean} sync
   *                 - {Boolean} lazy
   *                 - {Function} [preProcess]
   *                 - {Function} [postProcess]
   * @constructor
   */
  function Watcher(vm, expOrFn, cb, options) {
    // mix in options
    if (options) {
      extend(this, options);
    }
    var isFn = typeof expOrFn === 'function';
    this.vm = vm;
    vm._watchers.push(this);
    this.expression = expOrFn;
    this.cb = cb;
    this.id = ++uid$1; // uid for batching
    this.active = true;
    this.dirty = this.lazy; // for lazy watchers
    this.deps = [];
    this.newDeps = [];
    this.depIds = new Set$1();
    this.newDepIds = new Set$1();
    this.prevError = null; // for async error stacks
    // parse expression for getter/setter
    if (isFn) {
      this.getter = expOrFn;
      this.setter = undefined;
    } else {
      var res = parseExpression$1(expOrFn, this.twoWay);
      this.getter = res.get;
      this.setter = res.set;
    }
    this.value = this.lazy ? undefined : this.get();
    // state for avoiding false triggers for deep and Array
    // watchers during vm._digest()
    this.queued = this.shallow = false;
  }

  /**
   * Evaluate the getter, and re-collect dependencies.
   */

  Watcher.prototype.get = function () {
    this.beforeGet();
    var scope = this.scope || this.vm;
    var value;
    try {
      value = this.getter.call(scope, scope);
    } catch (e) {
      if ('development' !== 'production' && config.warnExpressionErrors) {
        warn('Error when evaluating expression ' + '"' + this.expression + '": ' + e.toString(), this.vm);
      }
    }
    // "touch" every property so they are all tracked as
    // dependencies for deep watching
    if (this.deep) {
      traverse(value);
    }
    if (this.preProcess) {
      value = this.preProcess(value);
    }
    if (this.filters) {
      value = scope._applyFilters(value, null, this.filters, false);
    }
    if (this.postProcess) {
      value = this.postProcess(value);
    }
    this.afterGet();
    return value;
  };

  /**
   * Set the corresponding value with the setter.
   *
   * @param {*} value
   */

  Watcher.prototype.set = function (value) {
    var scope = this.scope || this.vm;
    if (this.filters) {
      value = scope._applyFilters(value, this.value, this.filters, true);
    }
    try {
      this.setter.call(scope, scope, value);
    } catch (e) {
      if ('development' !== 'production' && config.warnExpressionErrors) {
        warn('Error when evaluating setter ' + '"' + this.expression + '": ' + e.toString(), this.vm);
      }
    }
    // two-way sync for v-for alias
    var forContext = scope.$forContext;
    if (forContext && forContext.alias === this.expression) {
      if (forContext.filters) {
        'development' !== 'production' && warn('It seems you are using two-way binding on ' + 'a v-for alias (' + this.expression + '), and the ' + 'v-for has filters. This will not work properly. ' + 'Either remove the filters or use an array of ' + 'objects and bind to object properties instead.', this.vm);
        return;
      }
      forContext._withLock(function () {
        if (scope.$key) {
          // original is an object
          forContext.rawValue[scope.$key] = value;
        } else {
          forContext.rawValue.$set(scope.$index, value);
        }
      });
    }
  };

  /**
   * Prepare for dependency collection.
   */

  Watcher.prototype.beforeGet = function () {
    Dep.target = this;
  };

  /**
   * Add a dependency to this directive.
   *
   * @param {Dep} dep
   */

  Watcher.prototype.addDep = function (dep) {
    var id = dep.id;
    if (!this.newDepIds.has(id)) {
      this.newDepIds.add(id);
      this.newDeps.push(dep);
      if (!this.depIds.has(id)) {
        dep.addSub(this);
      }
    }
  };

  /**
   * Clean up for dependency collection.
   */

  Watcher.prototype.afterGet = function () {
    Dep.target = null;
    var i = this.deps.length;
    while (i--) {
      var dep = this.deps[i];
      if (!this.newDepIds.has(dep.id)) {
        dep.removeSub(this);
      }
    }
    var tmp = this.depIds;
    this.depIds = this.newDepIds;
    this.newDepIds = tmp;
    this.newDepIds.clear();
    tmp = this.deps;
    this.deps = this.newDeps;
    this.newDeps = tmp;
    this.newDeps.length = 0;
  };

  /**
   * Subscriber interface.
   * Will be called when a dependency changes.
   *
   * @param {Boolean} shallow
   */

  Watcher.prototype.update = function (shallow) {
    if (this.lazy) {
      this.dirty = true;
    } else if (this.sync || !config.async) {
      this.run();
    } else {
      // if queued, only overwrite shallow with non-shallow,
      // but not the other way around.
      this.shallow = this.queued ? shallow ? this.shallow : false : !!shallow;
      this.queued = true;
      // record before-push error stack in debug mode
      /* istanbul ignore if */
      if ('development' !== 'production' && config.debug) {
        this.prevError = new Error('[vue] async stack trace');
      }
      pushWatcher(this);
    }
  };

  /**
   * Batcher job interface.
   * Will be called by the batcher.
   */

  Watcher.prototype.run = function () {
    if (this.active) {
      var value = this.get();
      if (value !== this.value ||
      // Deep watchers and watchers on Object/Arrays should fire even
      // when the value is the same, because the value may
      // have mutated; but only do so if this is a
      // non-shallow update (caused by a vm digest).
      (isObject(value) || this.deep) && !this.shallow) {
        // set new value
        var oldValue = this.value;
        this.value = value;
        // in debug + async mode, when a watcher callbacks
        // throws, we also throw the saved before-push error
        // so the full cross-tick stack trace is available.
        var prevError = this.prevError;
        /* istanbul ignore if */
        if ('development' !== 'production' && config.debug && prevError) {
          this.prevError = null;
          try {
            this.cb.call(this.vm, value, oldValue);
          } catch (e) {
            nextTick(function () {
              throw prevError;
            }, 0);
            throw e;
          }
        } else {
          this.cb.call(this.vm, value, oldValue);
        }
      }
      this.queued = this.shallow = false;
    }
  };

  /**
   * Evaluate the value of the watcher.
   * This only gets called for lazy watchers.
   */

  Watcher.prototype.evaluate = function () {
    // avoid overwriting another watcher that is being
    // collected.
    var current = Dep.target;
    this.value = this.get();
    this.dirty = false;
    Dep.target = current;
  };

  /**
   * Depend on all deps collected by this watcher.
   */

  Watcher.prototype.depend = function () {
    var i = this.deps.length;
    while (i--) {
      this.deps[i].depend();
    }
  };

  /**
   * Remove self from all dependencies' subcriber list.
   */

  Watcher.prototype.teardown = function () {
    if (this.active) {
      // remove self from vm's watcher list
      // this is a somewhat expensive operation so we skip it
      // if the vm is being destroyed or is performing a v-for
      // re-render (the watcher list is then filtered by v-for).
      if (!this.vm._isBeingDestroyed && !this.vm._vForRemoving) {
        this.vm._watchers.$remove(this);
      }
      var i = this.deps.length;
      while (i--) {
        this.deps[i].removeSub(this);
      }
      this.active = false;
      this.vm = this.cb = this.value = null;
    }
  };

  /**
   * Recrusively traverse an object to evoke all converted
   * getters, so that every nested property inside the object
   * is collected as a "deep" dependency.
   *
   * @param {*} val
   */

  var seenObjects = new Set$1();
  function traverse(val, seen) {
    var i = undefined,
        keys = undefined;
    if (!seen) {
      seen = seenObjects;
      seen.clear();
    }
    var isA = isArray(val);
    var isO = isObject(val);
    if ((isA || isO) && Object.isExtensible(val)) {
      if (val.__ob__) {
        var depId = val.__ob__.dep.id;
        if (seen.has(depId)) {
          return;
        } else {
          seen.add(depId);
        }
      }
      if (isA) {
        i = val.length;
        while (i--) traverse(val[i], seen);
      } else if (isO) {
        keys = Object.keys(val);
        i = keys.length;
        while (i--) traverse(val[keys[i]], seen);
      }
    }
  }

  var cloak = {
    bind: function bind() {
      var el = this.el;
      this.vm.$once('pre-hook:compiled', function () {
        el.removeAttribute('v-cloak');
      });
    }
  };

  var ref = {
    bind: function bind() {
      'development' !== 'production' && warn('v-ref:' + this.arg + ' must be used on a child ' + 'component. Found on <' + this.el.tagName.toLowerCase() + '>.', this.vm);
    }
  };

  var ON = 700;
  var MODEL = 800;
  var BIND = 850;
  var TRANSITION = 1100;
  var EL = 1500;
  var COMPONENT = 1500;
  var PARTIAL = 1750;
  var IF = 2100;
  var FOR = 2200;
  var SLOT = 2300;

  var el = {

    priority: EL,

    bind: function bind() {
      /* istanbul ignore if */
      if (!this.arg) {
        return;
      }
      var id = this.id = camelize(this.arg);
      var refs = (this._scope || this.vm).$els;
      if (hasOwn(refs, id)) {
        refs[id] = this.el;
      } else {
        defineReactive(refs, id, this.el);
      }
    },

    unbind: function unbind() {
      var refs = (this._scope || this.vm).$els;
      if (refs[this.id] === this.el) {
        refs[this.id] = null;
      }
    }
  };

  var prefixes = ['-webkit-', '-moz-', '-ms-'];
  var camelPrefixes = ['Webkit', 'Moz', 'ms'];
  var importantRE = /!important;?$/;
  var propCache = Object.create(null);

  var testEl = null;

  var vStyle = {

    deep: true,

    update: function update(value) {
      if (typeof value === 'string') {
        this.el.style.cssText = value;
      } else if (isArray(value)) {
        this.handleObject(value.reduce(extend, {}));
      } else {
        this.handleObject(value || {});
      }
    },

    handleObject: function handleObject(value) {
      // cache object styles so that only changed props
      // are actually updated.
      var cache = this.cache || (this.cache = {});
      var name, val;
      for (name in cache) {
        if (!(name in value)) {
          this.handleSingle(name, null);
          delete cache[name];
        }
      }
      for (name in value) {
        val = value[name];
        if (val !== cache[name]) {
          cache[name] = val;
          this.handleSingle(name, val);
        }
      }
    },

    handleSingle: function handleSingle(prop, value) {
      prop = normalize(prop);
      if (!prop) return; // unsupported prop
      // cast possible numbers/booleans into strings
      if (value != null) value += '';
      if (value) {
        var isImportant = importantRE.test(value) ? 'important' : '';
        if (isImportant) {
          /* istanbul ignore if */
          if ('development' !== 'production') {
            warn('It\'s probably a bad idea to use !important with inline rules. ' + 'This feature will be deprecated in a future version of Vue.');
          }
          value = value.replace(importantRE, '').trim();
          this.el.style.setProperty(prop.kebab, value, isImportant);
        } else {
          this.el.style[prop.camel] = value;
        }
      } else {
        this.el.style[prop.camel] = '';
      }
    }

  };

  /**
   * Normalize a CSS property name.
   * - cache result
   * - auto prefix
   * - camelCase -> dash-case
   *
   * @param {String} prop
   * @return {String}
   */

  function normalize(prop) {
    if (propCache[prop]) {
      return propCache[prop];
    }
    var res = prefix(prop);
    propCache[prop] = propCache[res] = res;
    return res;
  }

  /**
   * Auto detect the appropriate prefix for a CSS property.
   * https://gist.github.com/paulirish/523692
   *
   * @param {String} prop
   * @return {String}
   */

  function prefix(prop) {
    prop = hyphenate(prop);
    var camel = camelize(prop);
    var upper = camel.charAt(0).toUpperCase() + camel.slice(1);
    if (!testEl) {
      testEl = document.createElement('div');
    }
    var i = prefixes.length;
    var prefixed;
    if (camel !== 'filter' && camel in testEl.style) {
      return {
        kebab: prop,
        camel: camel
      };
    }
    while (i--) {
      prefixed = camelPrefixes[i] + upper;
      if (prefixed in testEl.style) {
        return {
          kebab: prefixes[i] + prop,
          camel: prefixed
        };
      }
    }
  }

  // xlink
  var xlinkNS = 'http://www.w3.org/1999/xlink';
  var xlinkRE = /^xlink:/;

  // check for attributes that prohibit interpolations
  var disallowedInterpAttrRE = /^v-|^:|^@|^(?:is|transition|transition-mode|debounce|track-by|stagger|enter-stagger|leave-stagger)$/;
  // these attributes should also set their corresponding properties
  // because they only affect the initial state of the element
  var attrWithPropsRE = /^(?:value|checked|selected|muted)$/;
  // these attributes expect enumrated values of "true" or "false"
  // but are not boolean attributes
  var enumeratedAttrRE = /^(?:draggable|contenteditable|spellcheck)$/;

  // these attributes should set a hidden property for
  // binding v-model to object values
  var modelProps = {
    value: '_value',
    'true-value': '_trueValue',
    'false-value': '_falseValue'
  };

  var bind$1 = {

    priority: BIND,

    bind: function bind() {
      var attr = this.arg;
      var tag = this.el.tagName;
      // should be deep watch on object mode
      if (!attr) {
        this.deep = true;
      }
      // handle interpolation bindings
      var descriptor = this.descriptor;
      var tokens = descriptor.interp;
      if (tokens) {
        // handle interpolations with one-time tokens
        if (descriptor.hasOneTime) {
          this.expression = tokensToExp(tokens, this._scope || this.vm);
        }

        // only allow binding on native attributes
        if (disallowedInterpAttrRE.test(attr) || attr === 'name' && (tag === 'PARTIAL' || tag === 'SLOT')) {
          'development' !== 'production' && warn(attr + '="' + descriptor.raw + '": ' + 'attribute interpolation is not allowed in Vue.js ' + 'directives and special attributes.', this.vm);
          this.el.removeAttribute(attr);
          this.invalid = true;
        }

        /* istanbul ignore if */
        if ('development' !== 'production') {
          var raw = attr + '="' + descriptor.raw + '": ';
          // warn src
          if (attr === 'src') {
            warn(raw + 'interpolation in "src" attribute will cause ' + 'a 404 request. Use v-bind:src instead.', this.vm);
          }

          // warn style
          if (attr === 'style') {
            warn(raw + 'interpolation in "style" attribute will cause ' + 'the attribute to be discarded in Internet Explorer. ' + 'Use v-bind:style instead.', this.vm);
          }
        }
      }
    },

    update: function update(value) {
      if (this.invalid) {
        return;
      }
      var attr = this.arg;
      if (this.arg) {
        this.handleSingle(attr, value);
      } else {
        this.handleObject(value || {});
      }
    },

    // share object handler with v-bind:class
    handleObject: vStyle.handleObject,

    handleSingle: function handleSingle(attr, value) {
      var el = this.el;
      var interp = this.descriptor.interp;
      if (this.modifiers.camel) {
        attr = camelize(attr);
      }
      if (!interp && attrWithPropsRE.test(attr) && attr in el) {
        var attrValue = attr === 'value' ? value == null // IE9 will set input.value to "null" for null...
        ? '' : value : value;

        if (el[attr] !== attrValue) {
          el[attr] = attrValue;
        }
      }
      // set model props
      var modelProp = modelProps[attr];
      if (!interp && modelProp) {
        el[modelProp] = value;
        // update v-model if present
        var model = el.__v_model;
        if (model) {
          model.listener();
        }
      }
      // do not set value attribute for textarea
      if (attr === 'value' && el.tagName === 'TEXTAREA') {
        el.removeAttribute(attr);
        return;
      }
      // update attribute
      if (enumeratedAttrRE.test(attr)) {
        el.setAttribute(attr, value ? 'true' : 'false');
      } else if (value != null && value !== false) {
        if (attr === 'class') {
          // handle edge case #1960:
          // class interpolation should not overwrite Vue transition class
          if (el.__v_trans) {
            value += ' ' + el.__v_trans.id + '-transition';
          }
          setClass(el, value);
        } else if (xlinkRE.test(attr)) {
          el.setAttributeNS(xlinkNS, attr, value === true ? '' : value);
        } else {
          el.setAttribute(attr, value === true ? '' : value);
        }
      } else {
        el.removeAttribute(attr);
      }
    }
  };

  // keyCode aliases
  var keyCodes = {
    esc: 27,
    tab: 9,
    enter: 13,
    space: 32,
    'delete': [8, 46],
    up: 38,
    left: 37,
    right: 39,
    down: 40
  };

  function keyFilter(handler, keys) {
    var codes = keys.map(function (key) {
      var charCode = key.charCodeAt(0);
      if (charCode > 47 && charCode < 58) {
        return parseInt(key, 10);
      }
      if (key.length === 1) {
        charCode = key.toUpperCase().charCodeAt(0);
        if (charCode > 64 && charCode < 91) {
          return charCode;
        }
      }
      return keyCodes[key];
    });
    codes = [].concat.apply([], codes);
    return function keyHandler(e) {
      if (codes.indexOf(e.keyCode) > -1) {
        return handler.call(this, e);
      }
    };
  }

  function stopFilter(handler) {
    return function stopHandler(e) {
      e.stopPropagation();
      return handler.call(this, e);
    };
  }

  function preventFilter(handler) {
    return function preventHandler(e) {
      e.preventDefault();
      return handler.call(this, e);
    };
  }

  function selfFilter(handler) {
    return function selfHandler(e) {
      if (e.target === e.currentTarget) {
        return handler.call(this, e);
      }
    };
  }

  var on$1 = {

    priority: ON,
    acceptStatement: true,
    keyCodes: keyCodes,

    bind: function bind() {
      // deal with iframes
      if (this.el.tagName === 'IFRAME' && this.arg !== 'load') {
        var self = this;
        this.iframeBind = function () {
          on(self.el.contentWindow, self.arg, self.handler, self.modifiers.capture);
        };
        this.on('load', this.iframeBind);
      }
    },

    update: function update(handler) {
      // stub a noop for v-on with no value,
      // e.g. @mousedown.prevent
      if (!this.descriptor.raw) {
        handler = function () {};
      }

      if (typeof handler !== 'function') {
        'development' !== 'production' && warn('v-on:' + this.arg + '="' + this.expression + '" expects a function value, ' + 'got ' + handler, this.vm);
        return;
      }

      // apply modifiers
      if (this.modifiers.stop) {
        handler = stopFilter(handler);
      }
      if (this.modifiers.prevent) {
        handler = preventFilter(handler);
      }
      if (this.modifiers.self) {
        handler = selfFilter(handler);
      }
      // key filter
      var keys = Object.keys(this.modifiers).filter(function (key) {
        return key !== 'stop' && key !== 'prevent' && key !== 'self' && key !== 'capture';
      });
      if (keys.length) {
        handler = keyFilter(handler, keys);
      }

      this.reset();
      this.handler = handler;

      if (this.iframeBind) {
        this.iframeBind();
      } else {
        on(this.el, this.arg, this.handler, this.modifiers.capture);
      }
    },

    reset: function reset() {
      var el = this.iframeBind ? this.el.contentWindow : this.el;
      if (this.handler) {
        off(el, this.arg, this.handler);
      }
    },

    unbind: function unbind() {
      this.reset();
    }
  };

  var checkbox = {

    bind: function bind() {
      var self = this;
      var el = this.el;

      this.getValue = function () {
        return el.hasOwnProperty('_value') ? el._value : self.params.number ? toNumber(el.value) : el.value;
      };

      function getBooleanValue() {
        var val = el.checked;
        if (val && el.hasOwnProperty('_trueValue')) {
          return el._trueValue;
        }
        if (!val && el.hasOwnProperty('_falseValue')) {
          return el._falseValue;
        }
        return val;
      }

      this.listener = function () {
        var model = self._watcher.get();
        if (isArray(model)) {
          var val = self.getValue();
          var i = indexOf(model, val);
          if (el.checked) {
            if (i < 0) {
              self.set(model.concat(val));
            }
          } else if (i > -1) {
            self.set(model.slice(0, i).concat(model.slice(i + 1)));
          }
        } else {
          self.set(getBooleanValue());
        }
      };

      this.on('change', this.listener);
      if (el.hasAttribute('checked')) {
        this.afterBind = this.listener;
      }
    },

    update: function update(value) {
      var el = this.el;
      if (isArray(value)) {
        el.checked = indexOf(value, this.getValue()) > -1;
      } else {
        if (el.hasOwnProperty('_trueValue')) {
          el.checked = looseEqual(value, el._trueValue);
        } else {
          el.checked = !!value;
        }
      }
    }
  };

  var select = {

    bind: function bind() {
      var _this = this;

      var self = this;
      var el = this.el;

      // method to force update DOM using latest value.
      this.forceUpdate = function () {
        if (self._watcher) {
          self.update(self._watcher.get());
        }
      };

      // check if this is a multiple select
      var multiple = this.multiple = el.hasAttribute('multiple');

      // attach listener
      this.listener = function () {
        var value = getValue(el, multiple);
        value = self.params.number ? isArray(value) ? value.map(toNumber) : toNumber(value) : value;
        self.set(value);
      };
      this.on('change', this.listener);

      // if has initial value, set afterBind
      var initValue = getValue(el, multiple, true);
      if (multiple && initValue.length || !multiple && initValue !== null) {
        this.afterBind = this.listener;
      }

      // All major browsers except Firefox resets
      // selectedIndex with value -1 to 0 when the element
      // is appended to a new parent, therefore we have to
      // force a DOM update whenever that happens...
      this.vm.$on('hook:attached', function () {
        nextTick(_this.forceUpdate);
      });
      if (!inDoc(el)) {
        nextTick(this.forceUpdate);
      }
    },

    update: function update(value) {
      var el = this.el;
      el.selectedIndex = -1;
      var multi = this.multiple && isArray(value);
      var options = el.options;
      var i = options.length;
      var op, val;
      while (i--) {
        op = options[i];
        val = op.hasOwnProperty('_value') ? op._value : op.value;
        /* eslint-disable eqeqeq */
        op.selected = multi ? indexOf$1(value, val) > -1 : looseEqual(value, val);
        /* eslint-enable eqeqeq */
      }
    },

    unbind: function unbind() {
      /* istanbul ignore next */
      this.vm.$off('hook:attached', this.forceUpdate);
    }
  };

  /**
   * Get select value
   *
   * @param {SelectElement} el
   * @param {Boolean} multi
   * @param {Boolean} init
   * @return {Array|*}
   */

  function getValue(el, multi, init) {
    var res = multi ? [] : null;
    var op, val, selected;
    for (var i = 0, l = el.options.length; i < l; i++) {
      op = el.options[i];
      selected = init ? op.hasAttribute('selected') : op.selected;
      if (selected) {
        val = op.hasOwnProperty('_value') ? op._value : op.value;
        if (multi) {
          res.push(val);
        } else {
          return val;
        }
      }
    }
    return res;
  }

  /**
   * Native Array.indexOf uses strict equal, but in this
   * case we need to match string/numbers with custom equal.
   *
   * @param {Array} arr
   * @param {*} val
   */

  function indexOf$1(arr, val) {
    var i = arr.length;
    while (i--) {
      if (looseEqual(arr[i], val)) {
        return i;
      }
    }
    return -1;
  }

  var radio = {

    bind: function bind() {
      var self = this;
      var el = this.el;

      this.getValue = function () {
        // value overwrite via v-bind:value
        if (el.hasOwnProperty('_value')) {
          return el._value;
        }
        var val = el.value;
        if (self.params.number) {
          val = toNumber(val);
        }
        return val;
      };

      this.listener = function () {
        self.set(self.getValue());
      };
      this.on('change', this.listener);

      if (el.hasAttribute('checked')) {
        this.afterBind = this.listener;
      }
    },

    update: function update(value) {
      this.el.checked = looseEqual(value, this.getValue());
    }
  };

  var text$2 = {

    bind: function bind() {
      var self = this;
      var el = this.el;
      var isRange = el.type === 'range';
      var lazy = this.params.lazy;
      var number = this.params.number;
      var debounce = this.params.debounce;

      // handle composition events.
      //   http://blog.evanyou.me/2014/01/03/composition-event/
      // skip this for Android because it handles composition
      // events quite differently. Android doesn't trigger
      // composition events for language input methods e.g.
      // Chinese, but instead triggers them for spelling
      // suggestions... (see Discussion/#162)
      var composing = false;
      if (!isAndroid && !isRange) {
        this.on('compositionstart', function () {
          composing = true;
        });
        this.on('compositionend', function () {
          composing = false;
          // in IE11 the "compositionend" event fires AFTER
          // the "input" event, so the input handler is blocked
          // at the end... have to call it here.
          //
          // #1327: in lazy mode this is unecessary.
          if (!lazy) {
            self.listener();
          }
        });
      }

      // prevent messing with the input when user is typing,
      // and force update on blur.
      this.focused = false;
      if (!isRange && !lazy) {
        this.on('focus', function () {
          self.focused = true;
        });
        this.on('blur', function () {
          self.focused = false;
          // do not sync value after fragment removal (#2017)
          if (!self._frag || self._frag.inserted) {
            self.rawListener();
          }
        });
      }

      // Now attach the main listener
      this.listener = this.rawListener = function () {
        if (composing || !self._bound) {
          return;
        }
        var val = number || isRange ? toNumber(el.value) : el.value;
        self.set(val);
        // force update on next tick to avoid lock & same value
        // also only update when user is not typing
        nextTick(function () {
          if (self._bound && !self.focused) {
            self.update(self._watcher.value);
          }
        });
      };

      // apply debounce
      if (debounce) {
        this.listener = _debounce(this.listener, debounce);
      }

      // Support jQuery events, since jQuery.trigger() doesn't
      // trigger native events in some cases and some plugins
      // rely on $.trigger()
      //
      // We want to make sure if a listener is attached using
      // jQuery, it is also removed with jQuery, that's why
      // we do the check for each directive instance and
      // store that check result on itself. This also allows
      // easier test coverage control by unsetting the global
      // jQuery variable in tests.
      this.hasjQuery = typeof jQuery === 'function';
      if (this.hasjQuery) {
        var method = jQuery.fn.on ? 'on' : 'bind';
        jQuery(el)[method]('change', this.rawListener);
        if (!lazy) {
          jQuery(el)[method]('input', this.listener);
        }
      } else {
        this.on('change', this.rawListener);
        if (!lazy) {
          this.on('input', this.listener);
        }
      }

      // IE9 doesn't fire input event on backspace/del/cut
      if (!lazy && isIE9) {
        this.on('cut', function () {
          nextTick(self.listener);
        });
        this.on('keyup', function (e) {
          if (e.keyCode === 46 || e.keyCode === 8) {
            self.listener();
          }
        });
      }

      // set initial value if present
      if (el.hasAttribute('value') || el.tagName === 'TEXTAREA' && el.value.trim()) {
        this.afterBind = this.listener;
      }
    },

    update: function update(value) {
      // #3029 only update when the value changes. This prevent
      // browsers from overwriting values like selectionStart
      value = _toString(value);
      if (value !== this.el.value) this.el.value = value;
    },

    unbind: function unbind() {
      var el = this.el;
      if (this.hasjQuery) {
        var method = jQuery.fn.off ? 'off' : 'unbind';
        jQuery(el)[method]('change', this.listener);
        jQuery(el)[method]('input', this.listener);
      }
    }
  };

  var handlers = {
    text: text$2,
    radio: radio,
    select: select,
    checkbox: checkbox
  };

  var model = {

    priority: MODEL,
    twoWay: true,
    handlers: handlers,
    params: ['lazy', 'number', 'debounce'],

    /**
     * Possible elements:
     *   <select>
     *   <textarea>
     *   <input type="*">
     *     - text
     *     - checkbox
     *     - radio
     *     - number
     */

    bind: function bind() {
      // friendly warning...
      this.checkFilters();
      if (this.hasRead && !this.hasWrite) {
        'development' !== 'production' && warn('It seems you are using a read-only filter with ' + 'v-model="' + this.descriptor.raw + '". ' + 'You might want to use a two-way filter to ensure correct behavior.', this.vm);
      }
      var el = this.el;
      var tag = el.tagName;
      var handler;
      if (tag === 'INPUT') {
        handler = handlers[el.type] || handlers.text;
      } else if (tag === 'SELECT') {
        handler = handlers.select;
      } else if (tag === 'TEXTAREA') {
        handler = handlers.text;
      } else {
        'development' !== 'production' && warn('v-model does not support element type: ' + tag, this.vm);
        return;
      }
      el.__v_model = this;
      handler.bind.call(this);
      this.update = handler.update;
      this._unbind = handler.unbind;
    },

    /**
     * Check read/write filter stats.
     */

    checkFilters: function checkFilters() {
      var filters = this.filters;
      if (!filters) return;
      var i = filters.length;
      while (i--) {
        var filter = resolveAsset(this.vm.$options, 'filters', filters[i].name);
        if (typeof filter === 'function' || filter.read) {
          this.hasRead = true;
        }
        if (filter.write) {
          this.hasWrite = true;
        }
      }
    },

    unbind: function unbind() {
      this.el.__v_model = null;
      this._unbind && this._unbind();
    }
  };

  var show = {

    bind: function bind() {
      // check else block
      var next = this.el.nextElementSibling;
      if (next && getAttr(next, 'v-else') !== null) {
        this.elseEl = next;
      }
    },

    update: function update(value) {
      this.apply(this.el, value);
      if (this.elseEl) {
        this.apply(this.elseEl, !value);
      }
    },

    apply: function apply(el, value) {
      if (inDoc(el)) {
        applyTransition(el, value ? 1 : -1, toggle, this.vm);
      } else {
        toggle();
      }
      function toggle() {
        el.style.display = value ? '' : 'none';
      }
    }
  };

  var templateCache = new Cache(1000);
  var idSelectorCache = new Cache(1000);

  var map = {
    efault: [0, '', ''],
    legend: [1, '<fieldset>', '</fieldset>'],
    tr: [2, '<table><tbody>', '</tbody></table>'],
    col: [2, '<table><tbody></tbody><colgroup>', '</colgroup></table>']
  };

  map.td = map.th = [3, '<table><tbody><tr>', '</tr></tbody></table>'];

  map.option = map.optgroup = [1, '<select multiple="multiple">', '</select>'];

  map.thead = map.tbody = map.colgroup = map.caption = map.tfoot = [1, '<table>', '</table>'];

  map.g = map.defs = map.symbol = map.use = map.image = map.text = map.circle = map.ellipse = map.line = map.path = map.polygon = map.polyline = map.rect = [1, '<svg ' + 'xmlns="http://www.w3.org/2000/svg" ' + 'xmlns:xlink="http://www.w3.org/1999/xlink" ' + 'xmlns:ev="http://www.w3.org/2001/xml-events"' + 'version="1.1">', '</svg>'];

  /**
   * Check if a node is a supported template node with a
   * DocumentFragment content.
   *
   * @param {Node} node
   * @return {Boolean}
   */

  function isRealTemplate(node) {
    return isTemplate(node) && isFragment(node.content);
  }

  var tagRE$1 = /<([\w:-]+)/;
  var entityRE = /&#?\w+?;/;
  var commentRE = /<!--/;

  /**
   * Convert a string template to a DocumentFragment.
   * Determines correct wrapping by tag types. Wrapping
   * strategy found in jQuery & component/domify.
   *
   * @param {String} templateString
   * @param {Boolean} raw
   * @return {DocumentFragment}
   */

  function stringToFragment(templateString, raw) {
    // try a cache hit first
    var cacheKey = raw ? templateString : templateString.trim();
    var hit = templateCache.get(cacheKey);
    if (hit) {
      return hit;
    }

    var frag = document.createDocumentFragment();
    var tagMatch = templateString.match(tagRE$1);
    var entityMatch = entityRE.test(templateString);
    var commentMatch = commentRE.test(templateString);

    if (!tagMatch && !entityMatch && !commentMatch) {
      // text only, return a single text node.
      frag.appendChild(document.createTextNode(templateString));
    } else {
      var tag = tagMatch && tagMatch[1];
      var wrap = map[tag] || map.efault;
      var depth = wrap[0];
      var prefix = wrap[1];
      var suffix = wrap[2];
      var node = document.createElement('div');

      node.innerHTML = prefix + templateString + suffix;
      while (depth--) {
        node = node.lastChild;
      }

      var child;
      /* eslint-disable no-cond-assign */
      while (child = node.firstChild) {
        /* eslint-enable no-cond-assign */
        frag.appendChild(child);
      }
    }
    if (!raw) {
      trimNode(frag);
    }
    templateCache.put(cacheKey, frag);
    return frag;
  }

  /**
   * Convert a template node to a DocumentFragment.
   *
   * @param {Node} node
   * @return {DocumentFragment}
   */

  function nodeToFragment(node) {
    // if its a template tag and the browser supports it,
    // its content is already a document fragment. However, iOS Safari has
    // bug when using directly cloned template content with touch
    // events and can cause crashes when the nodes are removed from DOM, so we
    // have to treat template elements as string templates. (#2805)
    /* istanbul ignore if */
    if (isRealTemplate(node)) {
      return stringToFragment(node.innerHTML);
    }
    // script template
    if (node.tagName === 'SCRIPT') {
      return stringToFragment(node.textContent);
    }
    // normal node, clone it to avoid mutating the original
    var clonedNode = cloneNode(node);
    var frag = document.createDocumentFragment();
    var child;
    /* eslint-disable no-cond-assign */
    while (child = clonedNode.firstChild) {
      /* eslint-enable no-cond-assign */
      frag.appendChild(child);
    }
    trimNode(frag);
    return frag;
  }

  // Test for the presence of the Safari template cloning bug
  // https://bugs.webkit.org/showug.cgi?id=137755
  var hasBrokenTemplate = (function () {
    /* istanbul ignore else */
    if (inBrowser) {
      var a = document.createElement('div');
      a.innerHTML = '<template>1</template>';
      return !a.cloneNode(true).firstChild.innerHTML;
    } else {
      return false;
    }
  })();

  // Test for IE10/11 textarea placeholder clone bug
  var hasTextareaCloneBug = (function () {
    /* istanbul ignore else */
    if (inBrowser) {
      var t = document.createElement('textarea');
      t.placeholder = 't';
      return t.cloneNode(true).value === 't';
    } else {
      return false;
    }
  })();

  /**
   * 1. Deal with Safari cloning nested <template> bug by
   *    manually cloning all template instances.
   * 2. Deal with IE10/11 textarea placeholder bug by setting
   *    the correct value after cloning.
   *
   * @param {Element|DocumentFragment} node
   * @return {Element|DocumentFragment}
   */

  function cloneNode(node) {
    /* istanbul ignore if */
    if (!node.querySelectorAll) {
      return node.cloneNode();
    }
    var res = node.cloneNode(true);
    var i, original, cloned;
    /* istanbul ignore if */
    if (hasBrokenTemplate) {
      var tempClone = res;
      if (isRealTemplate(node)) {
        node = node.content;
        tempClone = res.content;
      }
      original = node.querySelectorAll('template');
      if (original.length) {
        cloned = tempClone.querySelectorAll('template');
        i = cloned.length;
        while (i--) {
          cloned[i].parentNode.replaceChild(cloneNode(original[i]), cloned[i]);
        }
      }
    }
    /* istanbul ignore if */
    if (hasTextareaCloneBug) {
      if (node.tagName === 'TEXTAREA') {
        res.value = node.value;
      } else {
        original = node.querySelectorAll('textarea');
        if (original.length) {
          cloned = res.querySelectorAll('textarea');
          i = cloned.length;
          while (i--) {
            cloned[i].value = original[i].value;
          }
        }
      }
    }
    return res;
  }

  /**
   * Process the template option and normalizes it into a
   * a DocumentFragment that can be used as a partial or a
   * instance template.
   *
   * @param {*} template
   *        Possible values include:
   *        - DocumentFragment object
   *        - Node object of type Template
   *        - id selector: '#some-template-id'
   *        - template string: '<div><span>{{msg}}</span></div>'
   * @param {Boolean} shouldClone
   * @param {Boolean} raw
   *        inline HTML interpolation. Do not check for id
   *        selector and keep whitespace in the string.
   * @return {DocumentFragment|undefined}
   */

  function parseTemplate(template, shouldClone, raw) {
    var node, frag;

    // if the template is already a document fragment,
    // do nothing
    if (isFragment(template)) {
      trimNode(template);
      return shouldClone ? cloneNode(template) : template;
    }

    if (typeof template === 'string') {
      // id selector
      if (!raw && template.charAt(0) === '#') {
        // id selector can be cached too
        frag = idSelectorCache.get(template);
        if (!frag) {
          node = document.getElementById(template.slice(1));
          if (node) {
            frag = nodeToFragment(node);
            // save selector to cache
            idSelectorCache.put(template, frag);
          }
        }
      } else {
        // normal string template
        frag = stringToFragment(template, raw);
      }
    } else if (template.nodeType) {
      // a direct node
      frag = nodeToFragment(template);
    }

    return frag && shouldClone ? cloneNode(frag) : frag;
  }

  var template = Object.freeze({
    cloneNode: cloneNode,
    parseTemplate: parseTemplate
  });

  /**
   * Abstraction for a partially-compiled fragment.
   * Can optionally compile content with a child scope.
   *
   * @param {Function} linker
   * @param {Vue} vm
   * @param {DocumentFragment} frag
   * @param {Vue} [host]
   * @param {Object} [scope]
   * @param {Fragment} [parentFrag]
   */
  function Fragment(linker, vm, frag, host, scope, parentFrag) {
    this.children = [];
    this.childFrags = [];
    this.vm = vm;
    this.scope = scope;
    this.inserted = false;
    this.parentFrag = parentFrag;
    if (parentFrag) {
      parentFrag.childFrags.push(this);
    }
    this.unlink = linker(vm, frag, host, scope, this);
    var single = this.single = frag.childNodes.length === 1 &&
    // do not go single mode if the only node is an anchor
    !frag.childNodes[0].__v_anchor;
    if (single) {
      this.node = frag.childNodes[0];
      this.before = singleBefore;
      this.remove = singleRemove;
    } else {
      this.node = createAnchor('fragment-start');
      this.end = createAnchor('fragment-end');
      this.frag = frag;
      prepend(this.node, frag);
      frag.appendChild(this.end);
      this.before = multiBefore;
      this.remove = multiRemove;
    }
    this.node.__v_frag = this;
  }

  /**
   * Call attach/detach for all components contained within
   * this fragment. Also do so recursively for all child
   * fragments.
   *
   * @param {Function} hook
   */

  Fragment.prototype.callHook = function (hook) {
    var i, l;
    for (i = 0, l = this.childFrags.length; i < l; i++) {
      this.childFrags[i].callHook(hook);
    }
    for (i = 0, l = this.children.length; i < l; i++) {
      hook(this.children[i]);
    }
  };

  /**
   * Insert fragment before target, single node version
   *
   * @param {Node} target
   * @param {Boolean} withTransition
   */

  function singleBefore(target, withTransition) {
    this.inserted = true;
    var method = withTransition !== false ? beforeWithTransition : before;
    method(this.node, target, this.vm);
    if (inDoc(this.node)) {
      this.callHook(attach);
    }
  }

  /**
   * Remove fragment, single node version
   */

  function singleRemove() {
    this.inserted = false;
    var shouldCallRemove = inDoc(this.node);
    var self = this;
    this.beforeRemove();
    removeWithTransition(this.node, this.vm, function () {
      if (shouldCallRemove) {
        self.callHook(detach);
      }
      self.destroy();
    });
  }

  /**
   * Insert fragment before target, multi-nodes version
   *
   * @param {Node} target
   * @param {Boolean} withTransition
   */

  function multiBefore(target, withTransition) {
    this.inserted = true;
    var vm = this.vm;
    var method = withTransition !== false ? beforeWithTransition : before;
    mapNodeRange(this.node, this.end, function (node) {
      method(node, target, vm);
    });
    if (inDoc(this.node)) {
      this.callHook(attach);
    }
  }

  /**
   * Remove fragment, multi-nodes version
   */

  function multiRemove() {
    this.inserted = false;
    var self = this;
    var shouldCallRemove = inDoc(this.node);
    this.beforeRemove();
    removeNodeRange(this.node, this.end, this.vm, this.frag, function () {
      if (shouldCallRemove) {
        self.callHook(detach);
      }
      self.destroy();
    });
  }

  /**
   * Prepare the fragment for removal.
   */

  Fragment.prototype.beforeRemove = function () {
    var i, l;
    for (i = 0, l = this.childFrags.length; i < l; i++) {
      // call the same method recursively on child
      // fragments, depth-first
      this.childFrags[i].beforeRemove(false);
    }
    for (i = 0, l = this.children.length; i < l; i++) {
      // Call destroy for all contained instances,
      // with remove:false and defer:true.
      // Defer is necessary because we need to
      // keep the children to call detach hooks
      // on them.
      this.children[i].$destroy(false, true);
    }
    var dirs = this.unlink.dirs;
    for (i = 0, l = dirs.length; i < l; i++) {
      // disable the watchers on all the directives
      // so that the rendered content stays the same
      // during removal.
      dirs[i]._watcher && dirs[i]._watcher.teardown();
    }
  };

  /**
   * Destroy the fragment.
   */

  Fragment.prototype.destroy = function () {
    if (this.parentFrag) {
      this.parentFrag.childFrags.$remove(this);
    }
    this.node.__v_frag = null;
    this.unlink();
  };

  /**
   * Call attach hook for a Vue instance.
   *
   * @param {Vue} child
   */

  function attach(child) {
    if (!child._isAttached && inDoc(child.$el)) {
      child._callHook('attached');
    }
  }

  /**
   * Call detach hook for a Vue instance.
   *
   * @param {Vue} child
   */

  function detach(child) {
    if (child._isAttached && !inDoc(child.$el)) {
      child._callHook('detached');
    }
  }

  var linkerCache = new Cache(5000);

  /**
   * A factory that can be used to create instances of a
   * fragment. Caches the compiled linker if possible.
   *
   * @param {Vue} vm
   * @param {Element|String} el
   */
  function FragmentFactory(vm, el) {
    this.vm = vm;
    var template;
    var isString = typeof el === 'string';
    if (isString || isTemplate(el) && !el.hasAttribute('v-if')) {
      template = parseTemplate(el, true);
    } else {
      template = document.createDocumentFragment();
      template.appendChild(el);
    }
    this.template = template;
    // linker can be cached, but only for components
    var linker;
    var cid = vm.constructor.cid;
    if (cid > 0) {
      var cacheId = cid + (isString ? el : getOuterHTML(el));
      linker = linkerCache.get(cacheId);
      if (!linker) {
        linker = compile(template, vm.$options, true);
        linkerCache.put(cacheId, linker);
      }
    } else {
      linker = compile(template, vm.$options, true);
    }
    this.linker = linker;
  }

  /**
   * Create a fragment instance with given host and scope.
   *
   * @param {Vue} host
   * @param {Object} scope
   * @param {Fragment} parentFrag
   */

  FragmentFactory.prototype.create = function (host, scope, parentFrag) {
    var frag = cloneNode(this.template);
    return new Fragment(this.linker, this.vm, frag, host, scope, parentFrag);
  };

  var vIf = {

    priority: IF,
    terminal: true,

    bind: function bind() {
      var el = this.el;
      if (!el.__vue__) {
        // check else block
        var next = el.nextElementSibling;
        if (next && getAttr(next, 'v-else') !== null) {
          remove(next);
          this.elseEl = next;
        }
        // check main block
        this.anchor = createAnchor('v-if');
        replace(el, this.anchor);
      } else {
        'development' !== 'production' && warn('v-if="' + this.expression + '" cannot be ' + 'used on an instance root element.', this.vm);
        this.invalid = true;
      }
    },

    update: function update(value) {
      if (this.invalid) return;
      if (value) {
        if (!this.frag) {
          this.insert();
        }
      } else {
        this.remove();
      }
    },

    insert: function insert() {
      if (this.elseFrag) {
        this.elseFrag.remove();
        this.elseFrag = null;
      }
      // lazy init factory
      if (!this.factory) {
        this.factory = new FragmentFactory(this.vm, this.el);
      }
      this.frag = this.factory.create(this._host, this._scope, this._frag);
      this.frag.before(this.anchor);
    },

    remove: function remove() {
      if (this.frag) {
        this.frag.remove();
        this.frag = null;
      }
      if (this.elseEl && !this.elseFrag) {
        if (!this.elseFactory) {
          this.elseFactory = new FragmentFactory(this.elseEl._context || this.vm, this.elseEl);
        }
        this.elseFrag = this.elseFactory.create(this._host, this._scope, this._frag);
        this.elseFrag.before(this.anchor);
      }
    },

    unbind: function unbind() {
      if (this.frag) {
        this.frag.destroy();
      }
      if (this.elseFrag) {
        this.elseFrag.destroy();
      }
    }
  };

  var arrayProto = Array.prototype;
  var arrayMethods = Object.create(arrayProto)

  /**
   * Intercept mutating methods and emit events
   */

  ;['push', 'pop', 'shift', 'unshift', 'splice', 'sort', 'reverse'].forEach(function (method) {
    // cache original method
    var original = arrayProto[method];
    def(arrayMethods, method, function mutator() {
      // avoid leaking arguments:
      // http://jsperf.com/closure-with-arguments
      var i = arguments.length;
      var args = new Array(i);
      while (i--) {
        args[i] = arguments[i];
      }
      var result = original.apply(this, args);
      var ob = this.__ob__;
      var inserted;
      switch (method) {
        case 'push':
          inserted = args;
          break;
        case 'unshift':
          inserted = args;
          break;
        case 'splice':
          inserted = args.slice(2);
          break;
      }
      if (inserted) ob.observeArray(inserted);
      // notify change
      ob.dep.notify();
      return result;
    });
  });

  /**
   * Swap the element at the given index with a new value
   * and emits corresponding event.
   *
   * @param {Number} index
   * @param {*} val
   * @return {*} - replaced element
   */

  def(arrayProto, '$set', function $set(index, val) {
    if (index >= this.length) {
      this.length = Number(index) + 1;
    }
    return this.splice(index, 1, val)[0];
  });

  /**
   * Convenience method to remove the element at given index or target element reference.
   *
   * @param {*} item
   */

  def(arrayProto, '$remove', function $remove(item) {
    /* istanbul ignore if */
    if (!this.length) return;
    var index = indexOf(this, item);
    if (index > -1) {
      return this.splice(index, 1);
    }
  });

  var arrayKeys = Object.getOwnPropertyNames(arrayMethods);

  /**
   * By default, when a reactive property is set, the new value is
   * also converted to become reactive. However in certain cases, e.g.
   * v-for scope alias and props, we don't want to force conversion
   * because the value may be a nested value under a frozen data structure.
   *
   * So whenever we want to set a reactive property without forcing
   * conversion on the new value, we wrap that call inside this function.
   */

  var shouldConvert = true;

  function withoutConversion(fn) {
    shouldConvert = false;
    fn();
    shouldConvert = true;
  }

  /**
   * Observer class that are attached to each observed
   * object. Once attached, the observer converts target
   * object's property keys into getter/setters that
   * collect dependencies and dispatches updates.
   *
   * @param {Array|Object} value
   * @constructor
   */

  function Observer(value) {
    this.value = value;
    this.dep = new Dep();
    def(value, '__ob__', this);
    if (isArray(value)) {
      var augment = hasProto ? protoAugment : copyAugment;
      augment(value, arrayMethods, arrayKeys);
      this.observeArray(value);
    } else {
      this.walk(value);
    }
  }

  // Instance methods

  /**
   * Walk through each property and convert them into
   * getter/setters. This method should only be called when
   * value type is Object.
   *
   * @param {Object} obj
   */

  Observer.prototype.walk = function (obj) {
    var keys = Object.keys(obj);
    for (var i = 0, l = keys.length; i < l; i++) {
      this.convert(keys[i], obj[keys[i]]);
    }
  };

  /**
   * Observe a list of Array items.
   *
   * @param {Array} items
   */

  Observer.prototype.observeArray = function (items) {
    for (var i = 0, l = items.length; i < l; i++) {
      observe(items[i]);
    }
  };

  /**
   * Convert a property into getter/setter so we can emit
   * the events when the property is accessed/changed.
   *
   * @param {String} key
   * @param {*} val
   */

  Observer.prototype.convert = function (key, val) {
    defineReactive(this.value, key, val);
  };

  /**
   * Add an owner vm, so that when $set/$delete mutations
   * happen we can notify owner vms to proxy the keys and
   * digest the watchers. This is only called when the object
   * is observed as an instance's root $data.
   *
   * @param {Vue} vm
   */

  Observer.prototype.addVm = function (vm) {
    (this.vms || (this.vms = [])).push(vm);
  };

  /**
   * Remove an owner vm. This is called when the object is
   * swapped out as an instance's $data object.
   *
   * @param {Vue} vm
   */

  Observer.prototype.removeVm = function (vm) {
    this.vms.$remove(vm);
  };

  // helpers

  /**
   * Augment an target Object or Array by intercepting
   * the prototype chain using __proto__
   *
   * @param {Object|Array} target
   * @param {Object} src
   */

  function protoAugment(target, src) {
    /* eslint-disable no-proto */
    target.__proto__ = src;
    /* eslint-enable no-proto */
  }

  /**
   * Augment an target Object or Array by defining
   * hidden properties.
   *
   * @param {Object|Array} target
   * @param {Object} proto
   */

  function copyAugment(target, src, keys) {
    for (var i = 0, l = keys.length; i < l; i++) {
      var key = keys[i];
      def(target, key, src[key]);
    }
  }

  /**
   * Attempt to create an observer instance for a value,
   * returns the new observer if successfully observed,
   * or the existing observer if the value already has one.
   *
   * @param {*} value
   * @param {Vue} [vm]
   * @return {Observer|undefined}
   * @static
   */

  function observe(value, vm) {
    if (!value || typeof value !== 'object') {
      return;
    }
    var ob;
    if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) {
      ob = value.__ob__;
    } else if (shouldConvert && (isArray(value) || isPlainObject(value)) && Object.isExtensible(value) && !value._isVue) {
      ob = new Observer(value);
    }
    if (ob && vm) {
      ob.addVm(vm);
    }
    return ob;
  }

  /**
   * Define a reactive property on an Object.
   *
   * @param {Object} obj
   * @param {String} key
   * @param {*} val
   */

  function defineReactive(obj, key, val) {
    var dep = new Dep();

    var property = Object.getOwnPropertyDescriptor(obj, key);
    if (property && property.configurable === false) {
      return;
    }

    // cater for pre-defined getter/setters
    var getter = property && property.get;
    var setter = property && property.set;

    var childOb = observe(val);
    Object.defineProperty(obj, key, {
      enumerable: true,
      configurable: true,
      get: function reactiveGetter() {
        var value = getter ? getter.call(obj) : val;
        if (Dep.target) {
          dep.depend();
          if (childOb) {
            childOb.dep.depend();
          }
          if (isArray(value)) {
            for (var e, i = 0, l = value.length; i < l; i++) {
              e = value[i];
              e && e.__ob__ && e.__ob__.dep.depend();
            }
          }
        }
        return value;
      },
      set: function reactiveSetter(newVal) {
        var value = getter ? getter.call(obj) : val;
        if (newVal === value) {
          return;
        }
        if (setter) {
          setter.call(obj, newVal);
        } else {
          val = newVal;
        }
        childOb = observe(newVal);
        dep.notify();
      }
    });
  }

  var uid$3 = 0;

  var vFor = {

    priority: FOR,
    terminal: true,

    params: ['track-by', 'stagger', 'enter-stagger', 'leave-stagger'],

    bind: function bind() {
      if ('development' !== 'production' && this.el.hasAttribute('v-if')) {
        warn('<' + this.el.tagName.toLowerCase() + ' v-for="' + this.expression + '" v-if="' + this.el.getAttribute('v-if') + '">: ' + 'Using v-if and v-for on the same element is not recommended - ' + 'consider filtering the source Array instead.', this.vm);
      }

      // support "item in/of items" syntax
      var inMatch = this.expression.match(/(.*) (?:in|of) (.*)/);
      if (inMatch) {
        var itMatch = inMatch[1].match(/\((.*),(.*)\)/);
        if (itMatch) {
          this.iterator = itMatch[1].trim();
          this.alias = itMatch[2].trim();
        } else {
          this.alias = inMatch[1].trim();
        }
        this.expression = inMatch[2];
      }

      if (!this.alias) {
        'development' !== 'production' && warn('Invalid v-for expression "' + this.descriptor.raw + '": ' + 'alias is required.', this.vm);
        return;
      }

      // uid as a cache identifier
      this.id = '__v-for__' + ++uid$3;

      // check if this is an option list,
      // so that we know if we need to update the <select>'s
      // v-model when the option list has changed.
      // because v-model has a lower priority than v-for,
      // the v-model is not bound here yet, so we have to
      // retrive it in the actual updateModel() function.
      var tag = this.el.tagName;
      this.isOption = (tag === 'OPTION' || tag === 'OPTGROUP') && this.el.parentNode.tagName === 'SELECT';

      // setup anchor nodes
      this.start = createAnchor('v-for-start');
      this.end = createAnchor('v-for-end');
      replace(this.el, this.end);
      before(this.start, this.end);

      // cache
      this.cache = Object.create(null);

      // fragment factory
      this.factory = new FragmentFactory(this.vm, this.el);
    },

    update: function update(data) {
      this.diff(data);
      this.updateRef();
      this.updateModel();
    },

    /**
     * Diff, based on new data and old data, determine the
     * minimum amount of DOM manipulations needed to make the
     * DOM reflect the new data Array.
     *
     * The algorithm diffs the new data Array by storing a
     * hidden reference to an owner vm instance on previously
     * seen data. This allows us to achieve O(n) which is
     * better than a levenshtein distance based algorithm,
     * which is O(m * n).
     *
     * @param {Array} data
     */

    diff: function diff(data) {
      // check if the Array was converted from an Object
      var item = data[0];
      var convertedFromObject = this.fromObject = isObject(item) && hasOwn(item, '$key') && hasOwn(item, '$value');

      var trackByKey = this.params.trackBy;
      var oldFrags = this.frags;
      var frags = this.frags = new Array(data.length);
      var alias = this.alias;
      var iterator = this.iterator;
      var start = this.start;
      var end = this.end;
      var inDocument = inDoc(start);
      var init = !oldFrags;
      var i, l, frag, key, value, primitive;

      // First pass, go through the new Array and fill up
      // the new frags array. If a piece of data has a cached
      // instance for it, we reuse it. Otherwise build a new
      // instance.
      for (i = 0, l = data.length; i < l; i++) {
        item = data[i];
        key = convertedFromObject ? item.$key : null;
        value = convertedFromObject ? item.$value : item;
        primitive = !isObject(value);
        frag = !init && this.getCachedFrag(value, i, key);
        if (frag) {
          // reusable fragment
          frag.reused = true;
          // update $index
          frag.scope.$index = i;
          // update $key
          if (key) {
            frag.scope.$key = key;
          }
          // update iterator
          if (iterator) {
            frag.scope[iterator] = key !== null ? key : i;
          }
          // update data for track-by, object repeat &
          // primitive values.
          if (trackByKey || convertedFromObject || primitive) {
            withoutConversion(function () {
              frag.scope[alias] = value;
            });
          }
        } else {
          // new instance
          frag = this.create(value, alias, i, key);
          frag.fresh = !init;
        }
        frags[i] = frag;
        if (init) {
          frag.before(end);
        }
      }

      // we're done for the initial render.
      if (init) {
        return;
      }

      // Second pass, go through the old fragments and
      // destroy those who are not reused (and remove them
      // from cache)
      var removalIndex = 0;
      var totalRemoved = oldFrags.length - frags.length;
      // when removing a large number of fragments, watcher removal
      // turns out to be a perf bottleneck, so we batch the watcher
      // removals into a single filter call!
      this.vm._vForRemoving = true;
      for (i = 0, l = oldFrags.length; i < l; i++) {
        frag = oldFrags[i];
        if (!frag.reused) {
          this.deleteCachedFrag(frag);
          this.remove(frag, removalIndex++, totalRemoved, inDocument);
        }
      }
      this.vm._vForRemoving = false;
      if (removalIndex) {
        this.vm._watchers = this.vm._watchers.filter(function (w) {
          return w.active;
        });
      }

      // Final pass, move/insert new fragments into the
      // right place.
      var targetPrev, prevEl, currentPrev;
      var insertionIndex = 0;
      for (i = 0, l = frags.length; i < l; i++) {
        frag = frags[i];
        // this is the frag that we should be after
        targetPrev = frags[i - 1];
        prevEl = targetPrev ? targetPrev.staggerCb ? targetPrev.staggerAnchor : targetPrev.end || targetPrev.node : start;
        if (frag.reused && !frag.staggerCb) {
          currentPrev = findPrevFrag(frag, start, this.id);
          if (currentPrev !== targetPrev && (!currentPrev ||
          // optimization for moving a single item.
          // thanks to suggestions by @livoras in #1807
          findPrevFrag(currentPrev, start, this.id) !== targetPrev)) {
            this.move(frag, prevEl);
          }
        } else {
          // new instance, or still in stagger.
          // insert with updated stagger index.
          this.insert(frag, insertionIndex++, prevEl, inDocument);
        }
        frag.reused = frag.fresh = false;
      }
    },

    /**
     * Create a new fragment instance.
     *
     * @param {*} value
     * @param {String} alias
     * @param {Number} index
     * @param {String} [key]
     * @return {Fragment}
     */

    create: function create(value, alias, index, key) {
      var host = this._host;
      // create iteration scope
      var parentScope = this._scope || this.vm;
      var scope = Object.create(parentScope);
      // ref holder for the scope
      scope.$refs = Object.create(parentScope.$refs);
      scope.$els = Object.create(parentScope.$els);
      // make sure point $parent to parent scope
      scope.$parent = parentScope;
      // for two-way binding on alias
      scope.$forContext = this;
      // define scope properties
      // important: define the scope alias without forced conversion
      // so that frozen data structures remain non-reactive.
      withoutConversion(function () {
        defineReactive(scope, alias, value);
      });
      defineReactive(scope, '$index', index);
      if (key) {
        defineReactive(scope, '$key', key);
      } else if (scope.$key) {
        // avoid accidental fallback
        def(scope, '$key', null);
      }
      if (this.iterator) {
        defineReactive(scope, this.iterator, key !== null ? key : index);
      }
      var frag = this.factory.create(host, scope, this._frag);
      frag.forId = this.id;
      this.cacheFrag(value, frag, index, key);
      return frag;
    },

    /**
     * Update the v-ref on owner vm.
     */

    updateRef: function updateRef() {
      var ref = this.descriptor.ref;
      if (!ref) return;
      var hash = (this._scope || this.vm).$refs;
      var refs;
      if (!this.fromObject) {
        refs = this.frags.map(findVmFromFrag);
      } else {
        refs = {};
        this.frags.forEach(function (frag) {
          refs[frag.scope.$key] = findVmFromFrag(frag);
        });
      }
      hash[ref] = refs;
    },

    /**
     * For option lists, update the containing v-model on
     * parent <select>.
     */

    updateModel: function updateModel() {
      if (this.isOption) {
        var parent = this.start.parentNode;
        var model = parent && parent.__v_model;
        if (model) {
          model.forceUpdate();
        }
      }
    },

    /**
     * Insert a fragment. Handles staggering.
     *
     * @param {Fragment} frag
     * @param {Number} index
     * @param {Node} prevEl
     * @param {Boolean} inDocument
     */

    insert: function insert(frag, index, prevEl, inDocument) {
      if (frag.staggerCb) {
        frag.staggerCb.cancel();
        frag.staggerCb = null;
      }
      var staggerAmount = this.getStagger(frag, index, null, 'enter');
      if (inDocument && staggerAmount) {
        // create an anchor and insert it synchronously,
        // so that we can resolve the correct order without
        // worrying about some elements not inserted yet
        var anchor = frag.staggerAnchor;
        if (!anchor) {
          anchor = frag.staggerAnchor = createAnchor('stagger-anchor');
          anchor.__v_frag = frag;
        }
        after(anchor, prevEl);
        var op = frag.staggerCb = cancellable(function () {
          frag.staggerCb = null;
          frag.before(anchor);
          remove(anchor);
        });
        setTimeout(op, staggerAmount);
      } else {
        var target = prevEl.nextSibling;
        /* istanbul ignore if */
        if (!target) {
          // reset end anchor position in case the position was messed up
          // by an external drag-n-drop library.
          after(this.end, prevEl);
          target = this.end;
        }
        frag.before(target);
      }
    },

    /**
     * Remove a fragment. Handles staggering.
     *
     * @param {Fragment} frag
     * @param {Number} index
     * @param {Number} total
     * @param {Boolean} inDocument
     */

    remove: function remove(frag, index, total, inDocument) {
      if (frag.staggerCb) {
        frag.staggerCb.cancel();
        frag.staggerCb = null;
        // it's not possible for the same frag to be removed
        // twice, so if we have a pending stagger callback,
        // it means this frag is queued for enter but removed
        // before its transition started. Since it is already
        // destroyed, we can just leave it in detached state.
        return;
      }
      var staggerAmount = this.getStagger(frag, index, total, 'leave');
      if (inDocument && staggerAmount) {
        var op = frag.staggerCb = cancellable(function () {
          frag.staggerCb = null;
          frag.remove();
        });
        setTimeout(op, staggerAmount);
      } else {
        frag.remove();
      }
    },

    /**
     * Move a fragment to a new position.
     * Force no transition.
     *
     * @param {Fragment} frag
     * @param {Node} prevEl
     */

    move: function move(frag, prevEl) {
      // fix a common issue with Sortable:
      // if prevEl doesn't have nextSibling, this means it's
      // been dragged after the end anchor. Just re-position
      // the end anchor to the end of the container.
      /* istanbul ignore if */
      if (!prevEl.nextSibling) {
        this.end.parentNode.appendChild(this.end);
      }
      frag.before(prevEl.nextSibling, false);
    },

    /**
     * Cache a fragment using track-by or the object key.
     *
     * @param {*} value
     * @param {Fragment} frag
     * @param {Number} index
     * @param {String} [key]
     */

    cacheFrag: function cacheFrag(value, frag, index, key) {
      var trackByKey = this.params.trackBy;
      var cache = this.cache;
      var primitive = !isObject(value);
      var id;
      if (key || trackByKey || primitive) {
        id = getTrackByKey(index, key, value, trackByKey);
        if (!cache[id]) {
          cache[id] = frag;
        } else if (trackByKey !== '$index') {
          'development' !== 'production' && this.warnDuplicate(value);
        }
      } else {
        id = this.id;
        if (hasOwn(value, id)) {
          if (value[id] === null) {
            value[id] = frag;
          } else {
            'development' !== 'production' && this.warnDuplicate(value);
          }
        } else if (Object.isExtensible(value)) {
          def(value, id, frag);
        } else if ('development' !== 'production') {
          warn('Frozen v-for objects cannot be automatically tracked, make sure to ' + 'provide a track-by key.');
        }
      }
      frag.raw = value;
    },

    /**
     * Get a cached fragment from the value/index/key
     *
     * @param {*} value
     * @param {Number} index
     * @param {String} key
     * @return {Fragment}
     */

    getCachedFrag: function getCachedFrag(value, index, key) {
      var trackByKey = this.params.trackBy;
      var primitive = !isObject(value);
      var frag;
      if (key || trackByKey || primitive) {
        var id = getTrackByKey(index, key, value, trackByKey);
        frag = this.cache[id];
      } else {
        frag = value[this.id];
      }
      if (frag && (frag.reused || frag.fresh)) {
        'development' !== 'production' && this.warnDuplicate(value);
      }
      return frag;
    },

    /**
     * Delete a fragment from cache.
     *
     * @param {Fragment} frag
     */

    deleteCachedFrag: function deleteCachedFrag(frag) {
      var value = frag.raw;
      var trackByKey = this.params.trackBy;
      var scope = frag.scope;
      var index = scope.$index;
      // fix #948: avoid accidentally fall through to
      // a parent repeater which happens to have $key.
      var key = hasOwn(scope, '$key') && scope.$key;
      var primitive = !isObject(value);
      if (trackByKey || key || primitive) {
        var id = getTrackByKey(index, key, value, trackByKey);
        this.cache[id] = null;
      } else {
        value[this.id] = null;
        frag.raw = null;
      }
    },

    /**
     * Get the stagger amount for an insertion/removal.
     *
     * @param {Fragment} frag
     * @param {Number} index
     * @param {Number} total
     * @param {String} type
     */

    getStagger: function getStagger(frag, index, total, type) {
      type = type + 'Stagger';
      var trans = frag.node.__v_trans;
      var hooks = trans && trans.hooks;
      var hook = hooks && (hooks[type] || hooks.stagger);
      return hook ? hook.call(frag, index, total) : index * parseInt(this.params[type] || this.params.stagger, 10);
    },

    /**
     * Pre-process the value before piping it through the
     * filters. This is passed to and called by the watcher.
     */

    _preProcess: function _preProcess(value) {
      // regardless of type, store the un-filtered raw value.
      this.rawValue = value;
      return value;
    },

    /**
     * Post-process the value after it has been piped through
     * the filters. This is passed to and called by the watcher.
     *
     * It is necessary for this to be called during the
     * watcher's dependency collection phase because we want
     * the v-for to update when the source Object is mutated.
     */

    _postProcess: function _postProcess(value) {
      if (isArray(value)) {
        return value;
      } else if (isPlainObject(value)) {
        // convert plain object to array.
        var keys = Object.keys(value);
        var i = keys.length;
        var res = new Array(i);
        var key;
        while (i--) {
          key = keys[i];
          res[i] = {
            $key: key,
            $value: value[key]
          };
        }
        return res;
      } else {
        if (typeof value === 'number' && !isNaN(value)) {
          value = range(value);
        }
        return value || [];
      }
    },

    unbind: function unbind() {
      if (this.descriptor.ref) {
        (this._scope || this.vm).$refs[this.descriptor.ref] = null;
      }
      if (this.frags) {
        var i = this.frags.length;
        var frag;
        while (i--) {
          frag = this.frags[i];
          this.deleteCachedFrag(frag);
          frag.destroy();
        }
      }
    }
  };

  /**
   * Helper to find the previous element that is a fragment
   * anchor. This is necessary because a destroyed frag's
   * element could still be lingering in the DOM before its
   * leaving transition finishes, but its inserted flag
   * should have been set to false so we can skip them.
   *
   * If this is a block repeat, we want to make sure we only
   * return frag that is bound to this v-for. (see #929)
   *
   * @param {Fragment} frag
   * @param {Comment|Text} anchor
   * @param {String} id
   * @return {Fragment}
   */

  function findPrevFrag(frag, anchor, id) {
    var el = frag.node.previousSibling;
    /* istanbul ignore if */
    if (!el) return;
    frag = el.__v_frag;
    while ((!frag || frag.forId !== id || !frag.inserted) && el !== anchor) {
      el = el.previousSibling;
      /* istanbul ignore if */
      if (!el) return;
      frag = el.__v_frag;
    }
    return frag;
  }

  /**
   * Create a range array from given number.
   *
   * @param {Number} n
   * @return {Array}
   */

  function range(n) {
    var i = -1;
    var ret = new Array(Math.floor(n));
    while (++i < n) {
      ret[i] = i;
    }
    return ret;
  }

  /**
   * Get the track by key for an item.
   *
   * @param {Number} index
   * @param {String} key
   * @param {*} value
   * @param {String} [trackByKey]
   */

  function getTrackByKey(index, key, value, trackByKey) {
    return trackByKey ? trackByKey === '$index' ? index : trackByKey.charAt(0).match(/\w/) ? getPath(value, trackByKey) : value[trackByKey] : key || value;
  }

  if ('development' !== 'production') {
    vFor.warnDuplicate = function (value) {
      warn('Duplicate value found in v-for="' + this.descriptor.raw + '": ' + JSON.stringify(value) + '. Use track-by="$index" if ' + 'you are expecting duplicate values.', this.vm);
    };
  }

  /**
   * Find a vm from a fragment.
   *
   * @param {Fragment} frag
   * @return {Vue|undefined}
   */

  function findVmFromFrag(frag) {
    var node = frag.node;
    // handle multi-node frag
    if (frag.end) {
      while (!node.__vue__ && node !== frag.end && node.nextSibling) {
        node = node.nextSibling;
      }
    }
    return node.__vue__;
  }

  var html = {

    bind: function bind() {
      // a comment node means this is a binding for
      // {{{ inline unescaped html }}}
      if (this.el.nodeType === 8) {
        // hold nodes
        this.nodes = [];
        // replace the placeholder with proper anchor
        this.anchor = createAnchor('v-html');
        replace(this.el, this.anchor);
      }
    },

    update: function update(value) {
      value = _toString(value);
      if (this.nodes) {
        this.swap(value);
      } else {
        this.el.innerHTML = value;
      }
    },

    swap: function swap(value) {
      // remove old nodes
      var i = this.nodes.length;
      while (i--) {
        remove(this.nodes[i]);
      }
      // convert new value to a fragment
      // do not attempt to retrieve from id selector
      var frag = parseTemplate(value, true, true);
      // save a reference to these nodes so we can remove later
      this.nodes = toArray(frag.childNodes);
      before(frag, this.anchor);
    }
  };

  var text$1 = {

    bind: function bind() {
      this.attr = this.el.nodeType === 3 ? 'data' : 'textContent';
    },

    update: function update(value) {
      this.el[this.attr] = _toString(value);
    }
  };

  // must export plain object
  var publicDirectives = {
    text: text$1,
    html: html,
    'for': vFor,
    'if': vIf,
    show: show,
    model: model,
    on: on$1,
    bind: bind$1,
    el: el,
    ref: ref,
    cloak: cloak
  };

  var queue$1 = [];
  var queued = false;

  /**
   * Push a job into the queue.
   *
   * @param {Function} job
   */

  function pushJob(job) {
    queue$1.push(job);
    if (!queued) {
      queued = true;
      nextTick(flush);
    }
  }

  /**
   * Flush the queue, and do one forced reflow before
   * triggering transitions.
   */

  function flush() {
    // Force layout
    var f = document.documentElement.offsetHeight;
    for (var i = 0; i < queue$1.length; i++) {
      queue$1[i]();
    }
    queue$1 = [];
    queued = false;
    // dummy return, so js linters don't complain about
    // unused variable f
    return f;
  }

  var TYPE_TRANSITION = 'transition';
  var TYPE_ANIMATION = 'animation';
  var transDurationProp = transitionProp + 'Duration';
  var animDurationProp = animationProp + 'Duration';

  /**
   * If a just-entered element is applied the
   * leave class while its enter transition hasn't started yet,
   * and the transitioned property has the same value for both
   * enter/leave, then the leave transition will be skipped and
   * the transitionend event never fires. This function ensures
   * its callback to be called after a transition has started
   * by waiting for double raf.
   *
   * It falls back to setTimeout on devices that support CSS
   * transitions but not raf (e.g. Android 4.2 browser) - since
   * these environments are usually slow, we are giving it a
   * relatively large timeout.
   */

  var raf = inBrowser && window.requestAnimationFrame;
  var waitForTransitionStart = raf
  /* istanbul ignore next */
  ? function (fn) {
    raf(function () {
      raf(fn);
    });
  } : function (fn) {
    setTimeout(fn, 50);
  };

  /**
   * A Transition object that encapsulates the state and logic
   * of the transition.
   *
   * @param {Element} el
   * @param {String} id
   * @param {Object} hooks
   * @param {Vue} vm
   */
  function Transition(el, id, hooks, vm) {
    this.id = id;
    this.el = el;
    this.enterClass = hooks && hooks.enterClass || id + '-enter';
    this.leaveClass = hooks && hooks.leaveClass || id + '-leave';
    this.hooks = hooks;
    this.vm = vm;
    // async state
    this.pendingCssEvent = this.pendingCssCb = this.cancel = this.pendingJsCb = this.op = this.cb = null;
    this.justEntered = false;
    this.entered = this.left = false;
    this.typeCache = {};
    // check css transition type
    this.type = hooks && hooks.type;
    /* istanbul ignore if */
    if ('development' !== 'production') {
      if (this.type && this.type !== TYPE_TRANSITION && this.type !== TYPE_ANIMATION) {
        warn('invalid CSS transition type for transition="' + this.id + '": ' + this.type, vm);
      }
    }
    // bind
    var self = this;['enterNextTick', 'enterDone', 'leaveNextTick', 'leaveDone'].forEach(function (m) {
      self[m] = bind(self[m], self);
    });
  }

  var p$1 = Transition.prototype;

  /**
   * Start an entering transition.
   *
   * 1. enter transition triggered
   * 2. call beforeEnter hook
   * 3. add enter class
   * 4. insert/show element
   * 5. call enter hook (with possible explicit js callback)
   * 6. reflow
   * 7. based on transition type:
   *    - transition:
   *        remove class now, wait for transitionend,
   *        then done if there's no explicit js callback.
   *    - animation:
   *        wait for animationend, remove class,
   *        then done if there's no explicit js callback.
   *    - no css transition:
   *        done now if there's no explicit js callback.
   * 8. wait for either done or js callback, then call
   *    afterEnter hook.
   *
   * @param {Function} op - insert/show the element
   * @param {Function} [cb]
   */

  p$1.enter = function (op, cb) {
    this.cancelPending();
    this.callHook('beforeEnter');
    this.cb = cb;
    addClass(this.el, this.enterClass);
    op();
    this.entered = false;
    this.callHookWithCb('enter');
    if (this.entered) {
      return; // user called done synchronously.
    }
    this.cancel = this.hooks && this.hooks.enterCancelled;
    pushJob(this.enterNextTick);
  };

  /**
   * The "nextTick" phase of an entering transition, which is
   * to be pushed into a queue and executed after a reflow so
   * that removing the class can trigger a CSS transition.
   */

  p$1.enterNextTick = function () {
    var _this = this;

    // prevent transition skipping
    this.justEntered = true;
    waitForTransitionStart(function () {
      _this.justEntered = false;
    });
    var enterDone = this.enterDone;
    var type = this.getCssTransitionType(this.enterClass);
    if (!this.pendingJsCb) {
      if (type === TYPE_TRANSITION) {
        // trigger transition by removing enter class now
        removeClass(this.el, this.enterClass);
        this.setupCssCb(transitionEndEvent, enterDone);
      } else if (type === TYPE_ANIMATION) {
        this.setupCssCb(animationEndEvent, enterDone);
      } else {
        enterDone();
      }
    } else if (type === TYPE_TRANSITION) {
      removeClass(this.el, this.enterClass);
    }
  };

  /**
   * The "cleanup" phase of an entering transition.
   */

  p$1.enterDone = function () {
    this.entered = true;
    this.cancel = this.pendingJsCb = null;
    removeClass(this.el, this.enterClass);
    this.callHook('afterEnter');
    if (this.cb) this.cb();
  };

  /**
   * Start a leaving transition.
   *
   * 1. leave transition triggered.
   * 2. call beforeLeave hook
   * 3. add leave class (trigger css transition)
   * 4. call leave hook (with possible explicit js callback)
   * 5. reflow if no explicit js callback is provided
   * 6. based on transition type:
   *    - transition or animation:
   *        wait for end event, remove class, then done if
   *        there's no explicit js callback.
   *    - no css transition:
   *        done if there's no explicit js callback.
   * 7. wait for either done or js callback, then call
   *    afterLeave hook.
   *
   * @param {Function} op - remove/hide the element
   * @param {Function} [cb]
   */

  p$1.leave = function (op, cb) {
    this.cancelPending();
    this.callHook('beforeLeave');
    this.op = op;
    this.cb = cb;
    addClass(this.el, this.leaveClass);
    this.left = false;
    this.callHookWithCb('leave');
    if (this.left) {
      return; // user called done synchronously.
    }
    this.cancel = this.hooks && this.hooks.leaveCancelled;
    // only need to handle leaveDone if
    // 1. the transition is already done (synchronously called
    //    by the user, which causes this.op set to null)
    // 2. there's no explicit js callback
    if (this.op && !this.pendingJsCb) {
      // if a CSS transition leaves immediately after enter,
      // the transitionend event never fires. therefore we
      // detect such cases and end the leave immediately.
      if (this.justEntered) {
        this.leaveDone();
      } else {
        pushJob(this.leaveNextTick);
      }
    }
  };

  /**
   * The "nextTick" phase of a leaving transition.
   */

  p$1.leaveNextTick = function () {
    var type = this.getCssTransitionType(this.leaveClass);
    if (type) {
      var event = type === TYPE_TRANSITION ? transitionEndEvent : animationEndEvent;
      this.setupCssCb(event, this.leaveDone);
    } else {
      this.leaveDone();
    }
  };

  /**
   * The "cleanup" phase of a leaving transition.
   */

  p$1.leaveDone = function () {
    this.left = true;
    this.cancel = this.pendingJsCb = null;
    this.op();
    removeClass(this.el, this.leaveClass);
    this.callHook('afterLeave');
    if (this.cb) this.cb();
    this.op = null;
  };

  /**
   * Cancel any pending callbacks from a previously running
   * but not finished transition.
   */

  p$1.cancelPending = function () {
    this.op = this.cb = null;
    var hasPending = false;
    if (this.pendingCssCb) {
      hasPending = true;
      off(this.el, this.pendingCssEvent, this.pendingCssCb);
      this.pendingCssEvent = this.pendingCssCb = null;
    }
    if (this.pendingJsCb) {
      hasPending = true;
      this.pendingJsCb.cancel();
      this.pendingJsCb = null;
    }
    if (hasPending) {
      removeClass(this.el, this.enterClass);
      removeClass(this.el, this.leaveClass);
    }
    if (this.cancel) {
      this.cancel.call(this.vm, this.el);
      this.cancel = null;
    }
  };

  /**
   * Call a user-provided synchronous hook function.
   *
   * @param {String} type
   */

  p$1.callHook = function (type) {
    if (this.hooks && this.hooks[type]) {
      this.hooks[type].call(this.vm, this.el);
    }
  };

  /**
   * Call a user-provided, potentially-async hook function.
   * We check for the length of arguments to see if the hook
   * expects a `done` callback. If true, the transition's end
   * will be determined by when the user calls that callback;
   * otherwise, the end is determined by the CSS transition or
   * animation.
   *
   * @param {String} type
   */

  p$1.callHookWithCb = function (type) {
    var hook = this.hooks && this.hooks[type];
    if (hook) {
      if (hook.length > 1) {
        this.pendingJsCb = cancellable(this[type + 'Done']);
      }
      hook.call(this.vm, this.el, this.pendingJsCb);
    }
  };

  /**
   * Get an element's transition type based on the
   * calculated styles.
   *
   * @param {String} className
   * @return {Number}
   */

  p$1.getCssTransitionType = function (className) {
    /* istanbul ignore if */
    if (!transitionEndEvent ||
    // skip CSS transitions if page is not visible -
    // this solves the issue of transitionend events not
    // firing until the page is visible again.
    // pageVisibility API is supported in IE10+, same as
    // CSS transitions.
    document.hidden ||
    // explicit js-only transition
    this.hooks && this.hooks.css === false ||
    // element is hidden
    isHidden(this.el)) {
      return;
    }
    var type = this.type || this.typeCache[className];
    if (type) return type;
    var inlineStyles = this.el.style;
    var computedStyles = window.getComputedStyle(this.el);
    var transDuration = inlineStyles[transDurationProp] || computedStyles[transDurationProp];
    if (transDuration && transDuration !== '0s') {
      type = TYPE_TRANSITION;
    } else {
      var animDuration = inlineStyles[animDurationProp] || computedStyles[animDurationProp];
      if (animDuration && animDuration !== '0s') {
        type = TYPE_ANIMATION;
      }
    }
    if (type) {
      this.typeCache[className] = type;
    }
    return type;
  };

  /**
   * Setup a CSS transitionend/animationend callback.
   *
   * @param {String} event
   * @param {Function} cb
   */

  p$1.setupCssCb = function (event, cb) {
    this.pendingCssEvent = event;
    var self = this;
    var el = this.el;
    var onEnd = this.pendingCssCb = function (e) {
      if (e.target === el) {
        off(el, event, onEnd);
        self.pendingCssEvent = self.pendingCssCb = null;
        if (!self.pendingJsCb && cb) {
          cb();
        }
      }
    };
    on(el, event, onEnd);
  };

  /**
   * Check if an element is hidden - in that case we can just
   * skip the transition alltogether.
   *
   * @param {Element} el
   * @return {Boolean}
   */

  function isHidden(el) {
    if (/svg$/.test(el.namespaceURI)) {
      // SVG elements do not have offset(Width|Height)
      // so we need to check the client rect
      var rect = el.getBoundingClientRect();
      return !(rect.width || rect.height);
    } else {
      return !(el.offsetWidth || el.offsetHeight || el.getClientRects().length);
    }
  }

  var transition$1 = {

    priority: TRANSITION,

    update: function update(id, oldId) {
      var el = this.el;
      // resolve on owner vm
      var hooks = resolveAsset(this.vm.$options, 'transitions', id);
      id = id || 'v';
      oldId = oldId || 'v';
      el.__v_trans = new Transition(el, id, hooks, this.vm);
      removeClass(el, oldId + '-transition');
      addClass(el, id + '-transition');
    }
  };

  var propBindingModes = config._propBindingModes;
  var empty = {};

  // regexes
  var identRE$1 = /^[$_a-zA-Z]+[\w$]*$/;
  var settablePathRE = /^[A-Za-z_$][\w$]*(\.[A-Za-z_$][\w$]*|\[[^\[\]]+\])*$/;

  /**
   * Compile props on a root element and return
   * a props link function.
   *
   * @param {Element|DocumentFragment} el
   * @param {Array} propOptions
   * @param {Vue} vm
   * @return {Function} propsLinkFn
   */

  function compileProps(el, propOptions, vm) {
    var props = [];
    var propsData = vm.$options.propsData;
    var names = Object.keys(propOptions);
    var i = names.length;
    var options, name, attr, value, path, parsed, prop;
    while (i--) {
      name = names[i];
      options = propOptions[name] || empty;

      if ('development' !== 'production' && name === '$data') {
        warn('Do not use $data as prop.', vm);
        continue;
      }

      // props could contain dashes, which will be
      // interpreted as minus calculations by the parser
      // so we need to camelize the path here
      path = camelize(name);
      if (!identRE$1.test(path)) {
        'development' !== 'production' && warn('Invalid prop key: "' + name + '". Prop keys ' + 'must be valid identifiers.', vm);
        continue;
      }

      prop = {
        name: name,
        path: path,
        options: options,
        mode: propBindingModes.ONE_WAY,
        raw: null
      };

      attr = hyphenate(name);
      // first check dynamic version
      if ((value = getBindAttr(el, attr)) === null) {
        if ((value = getBindAttr(el, attr + '.sync')) !== null) {
          prop.mode = propBindingModes.TWO_WAY;
        } else if ((value = getBindAttr(el, attr + '.once')) !== null) {
          prop.mode = propBindingModes.ONE_TIME;
        }
      }
      if (value !== null) {
        // has dynamic binding!
        prop.raw = value;
        parsed = parseDirective(value);
        value = parsed.expression;
        prop.filters = parsed.filters;
        // check binding type
        if (isLiteral(value) && !parsed.filters) {
          // for expressions containing literal numbers and
          // booleans, there's no need to setup a prop binding,
          // so we can optimize them as a one-time set.
          prop.optimizedLiteral = true;
        } else {
          prop.dynamic = true;
          // check non-settable path for two-way bindings
          if ('development' !== 'production' && prop.mode === propBindingModes.TWO_WAY && !settablePathRE.test(value)) {
            prop.mode = propBindingModes.ONE_WAY;
            warn('Cannot bind two-way prop with non-settable ' + 'parent path: ' + value, vm);
          }
        }
        prop.parentPath = value;

        // warn required two-way
        if ('development' !== 'production' && options.twoWay && prop.mode !== propBindingModes.TWO_WAY) {
          warn('Prop "' + name + '" expects a two-way binding type.', vm);
        }
      } else if ((value = getAttr(el, attr)) !== null) {
        // has literal binding!
        prop.raw = value;
      } else if (propsData && (value = propsData[name] || propsData[path]) !== null) {
        // has propsData
        prop.raw = value;
      } else if ('development' !== 'production') {
        // check possible camelCase prop usage
        var lowerCaseName = path.toLowerCase();
        value = /[A-Z\-]/.test(name) && (el.getAttribute(lowerCaseName) || el.getAttribute(':' + lowerCaseName) || el.getAttribute('v-bind:' + lowerCaseName) || el.getAttribute(':' + lowerCaseName + '.once') || el.getAttribute('v-bind:' + lowerCaseName + '.once') || el.getAttribute(':' + lowerCaseName + '.sync') || el.getAttribute('v-bind:' + lowerCaseName + '.sync'));
        if (value) {
          warn('Possible usage error for prop `' + lowerCaseName + '` - ' + 'did you mean `' + attr + '`? HTML is case-insensitive, remember to use ' + 'kebab-case for props in templates.', vm);
        } else if (options.required && (!propsData || !(name in propsData) && !(path in propsData))) {
          // warn missing required
          warn('Missing required prop: ' + name, vm);
        }
      }
      // push prop
      props.push(prop);
    }
    return makePropsLinkFn(props);
  }

  /**
   * Build a function that applies props to a vm.
   *
   * @param {Array} props
   * @return {Function} propsLinkFn
   */

  function makePropsLinkFn(props) {
    return function propsLinkFn(vm, scope) {
      // store resolved props info
      vm._props = {};
      var inlineProps = vm.$options.propsData;
      var i = props.length;
      var prop, path, options, value, raw;
      while (i--) {
        prop = props[i];
        raw = prop.raw;
        path = prop.path;
        options = prop.options;
        vm._props[path] = prop;
        if (inlineProps && hasOwn(inlineProps, path)) {
          initProp(vm, prop, inlineProps[path]);
        }if (raw === null) {
          // initialize absent prop
          initProp(vm, prop, undefined);
        } else if (prop.dynamic) {
          // dynamic prop
          if (prop.mode === propBindingModes.ONE_TIME) {
            // one time binding
            value = (scope || vm._context || vm).$get(prop.parentPath);
            initProp(vm, prop, value);
          } else {
            if (vm._context) {
              // dynamic binding
              vm._bindDir({
                name: 'prop',
                def: propDef,
                prop: prop
              }, null, null, scope); // el, host, scope
            } else {
                // root instance
                initProp(vm, prop, vm.$get(prop.parentPath));
              }
          }
        } else if (prop.optimizedLiteral) {
          // optimized literal, cast it and just set once
          var stripped = stripQuotes(raw);
          value = stripped === raw ? toBoolean(toNumber(raw)) : stripped;
          initProp(vm, prop, value);
        } else {
          // string literal, but we need to cater for
          // Boolean props with no value, or with same
          // literal value (e.g. disabled="disabled")
          // see https://github.com/vuejs/vue-loader/issues/182
          value = options.type === Boolean && (raw === '' || raw === hyphenate(prop.name)) ? true : raw;
          initProp(vm, prop, value);
        }
      }
    };
  }

  /**
   * Process a prop with a rawValue, applying necessary coersions,
   * default values & assertions and call the given callback with
   * processed value.
   *
   * @param {Vue} vm
   * @param {Object} prop
   * @param {*} rawValue
   * @param {Function} fn
   */

  function processPropValue(vm, prop, rawValue, fn) {
    var isSimple = prop.dynamic && isSimplePath(prop.parentPath);
    var value = rawValue;
    if (value === undefined) {
      value = getPropDefaultValue(vm, prop);
    }
    value = coerceProp(prop, value, vm);
    var coerced = value !== rawValue;
    if (!assertProp(prop, value, vm)) {
      value = undefined;
    }
    if (isSimple && !coerced) {
      withoutConversion(function () {
        fn(value);
      });
    } else {
      fn(value);
    }
  }

  /**
   * Set a prop's initial value on a vm and its data object.
   *
   * @param {Vue} vm
   * @param {Object} prop
   * @param {*} value
   */

  function initProp(vm, prop, value) {
    processPropValue(vm, prop, value, function (value) {
      defineReactive(vm, prop.path, value);
    });
  }

  /**
   * Update a prop's value on a vm.
   *
   * @param {Vue} vm
   * @param {Object} prop
   * @param {*} value
   */

  function updateProp(vm, prop, value) {
    processPropValue(vm, prop, value, function (value) {
      vm[prop.path] = value;
    });
  }

  /**
   * Get the default value of a prop.
   *
   * @param {Vue} vm
   * @param {Object} prop
   * @return {*}
   */

  function getPropDefaultValue(vm, prop) {
    // no default, return undefined
    var options = prop.options;
    if (!hasOwn(options, 'default')) {
      // absent boolean value defaults to false
      return options.type === Boolean ? false : undefined;
    }
    var def = options['default'];
    // warn against non-factory defaults for Object & Array
    if (isObject(def)) {
      'development' !== 'production' && warn('Invalid default value for prop "' + prop.name + '": ' + 'Props with type Object/Array must use a factory function ' + 'to return the default value.', vm);
    }
    // call factory function for non-Function types
    return typeof def === 'function' && options.type !== Function ? def.call(vm) : def;
  }

  /**
   * Assert whether a prop is valid.
   *
   * @param {Object} prop
   * @param {*} value
   * @param {Vue} vm
   */

  function assertProp(prop, value, vm) {
    if (!prop.options.required && ( // non-required
    prop.raw === null || // abscent
    value == null) // null or undefined
    ) {
        return true;
      }
    var options = prop.options;
    var type = options.type;
    var valid = !type;
    var expectedTypes = [];
    if (type) {
      if (!isArray(type)) {
        type = [type];
      }
      for (var i = 0; i < type.length && !valid; i++) {
        var assertedType = assertType(value, type[i]);
        expectedTypes.push(assertedType.expectedType);
        valid = assertedType.valid;
      }
    }
    if (!valid) {
      if ('development' !== 'production') {
        warn('Invalid prop: type check failed for prop "' + prop.name + '".' + ' Expected ' + expectedTypes.map(formatType).join(', ') + ', got ' + formatValue(value) + '.', vm);
      }
      return false;
    }
    var validator = options.validator;
    if (validator) {
      if (!validator(value)) {
        'development' !== 'production' && warn('Invalid prop: custom validator check failed for prop "' + prop.name + '".', vm);
        return false;
      }
    }
    return true;
  }

  /**
   * Force parsing value with coerce option.
   *
   * @param {*} value
   * @param {Object} options
   * @return {*}
   */

  function coerceProp(prop, value, vm) {
    var coerce = prop.options.coerce;
    if (!coerce) {
      return value;
    }
    if (typeof coerce === 'function') {
      return coerce(value);
    } else {
      'development' !== 'production' && warn('Invalid coerce for prop "' + prop.name + '": expected function, got ' + typeof coerce + '.', vm);
      return value;
    }
  }

  /**
   * Assert the type of a value
   *
   * @param {*} value
   * @param {Function} type
   * @return {Object}
   */

  function assertType(value, type) {
    var valid;
    var expectedType;
    if (type === String) {
      expectedType = 'string';
      valid = typeof value === expectedType;
    } else if (type === Number) {
      expectedType = 'number';
      valid = typeof value === expectedType;
    } else if (type === Boolean) {
      expectedType = 'boolean';
      valid = typeof value === expectedType;
    } else if (type === Function) {
      expectedType = 'function';
      valid = typeof value === expectedType;
    } else if (type === Object) {
      expectedType = 'object';
      valid = isPlainObject(value);
    } else if (type === Array) {
      expectedType = 'array';
      valid = isArray(value);
    } else {
      valid = value instanceof type;
    }
    return {
      valid: valid,
      expectedType: expectedType
    };
  }

  /**
   * Format type for output
   *
   * @param {String} type
   * @return {String}
   */

  function formatType(type) {
    return type ? type.charAt(0).toUpperCase() + type.slice(1) : 'custom type';
  }

  /**
   * Format value
   *
   * @param {*} value
   * @return {String}
   */

  function formatValue(val) {
    return Object.prototype.toString.call(val).slice(8, -1);
  }

  var bindingModes = config._propBindingModes;

  var propDef = {

    bind: function bind() {
      var child = this.vm;
      var parent = child._context;
      // passed in from compiler directly
      var prop = this.descriptor.prop;
      var childKey = prop.path;
      var parentKey = prop.parentPath;
      var twoWay = prop.mode === bindingModes.TWO_WAY;

      var parentWatcher = this.parentWatcher = new Watcher(parent, parentKey, function (val) {
        updateProp(child, prop, val);
      }, {
        twoWay: twoWay,
        filters: prop.filters,
        // important: props need to be observed on the
        // v-for scope if present
        scope: this._scope
      });

      // set the child initial value.
      initProp(child, prop, parentWatcher.value);

      // setup two-way binding
      if (twoWay) {
        // important: defer the child watcher creation until
        // the created hook (after data observation)
        var self = this;
        child.$once('pre-hook:created', function () {
          self.childWatcher = new Watcher(child, childKey, function (val) {
            parentWatcher.set(val);
          }, {
            // ensure sync upward before parent sync down.
            // this is necessary in cases e.g. the child
            // mutates a prop array, then replaces it. (#1683)
            sync: true
          });
        });
      }
    },

    unbind: function unbind() {
      this.parentWatcher.teardown();
      if (this.childWatcher) {
        this.childWatcher.teardown();
      }
    }
  };

  var component = {

    priority: COMPONENT,

    params: ['keep-alive', 'transition-mode', 'inline-template'],

    /**
     * Setup. Two possible usages:
     *
     * - static:
     *   <comp> or <div v-component="comp">
     *
     * - dynamic:
     *   <component :is="view">
     */

    bind: function bind() {
      if (!this.el.__vue__) {
        // keep-alive cache
        this.keepAlive = this.params.keepAlive;
        if (this.keepAlive) {
          this.cache = {};
        }
        // check inline-template
        if (this.params.inlineTemplate) {
          // extract inline template as a DocumentFragment
          this.inlineTemplate = extractContent(this.el, true);
        }
        // component resolution related state
        this.pendingComponentCb = this.Component = null;
        // transition related state
        this.pendingRemovals = 0;
        this.pendingRemovalCb = null;
        // create a ref anchor
        this.anchor = createAnchor('v-component');
        replace(this.el, this.anchor);
        // remove is attribute.
        // this is removed during compilation, but because compilation is
        // cached, when the component is used elsewhere this attribute
        // will remain at link time.
        this.el.removeAttribute('is');
        this.el.removeAttribute(':is');
        // remove ref, same as above
        if (this.descriptor.ref) {
          this.el.removeAttribute('v-ref:' + hyphenate(this.descriptor.ref));
        }
        // if static, build right now.
        if (this.literal) {
          this.setComponent(this.expression);
        }
      } else {
        'development' !== 'production' && warn('cannot mount component "' + this.expression + '" ' + 'on already mounted element: ' + this.el);
      }
    },

    /**
     * Public update, called by the watcher in the dynamic
     * literal scenario, e.g. <component :is="view">
     */

    update: function update(value) {
      if (!this.literal) {
        this.setComponent(value);
      }
    },

    /**
     * Switch dynamic components. May resolve the component
     * asynchronously, and perform transition based on
     * specified transition mode. Accepts a few additional
     * arguments specifically for vue-router.
     *
     * The callback is called when the full transition is
     * finished.
     *
     * @param {String} value
     * @param {Function} [cb]
     */

    setComponent: function setComponent(value, cb) {
      this.invalidatePending();
      if (!value) {
        // just remove current
        this.unbuild(true);
        this.remove(this.childVM, cb);
        this.childVM = null;
      } else {
        var self = this;
        this.resolveComponent(value, function () {
          self.mountComponent(cb);
        });
      }
    },

    /**
     * Resolve the component constructor to use when creating
     * the child vm.
     *
     * @param {String|Function} value
     * @param {Function} cb
     */

    resolveComponent: function resolveComponent(value, cb) {
      var self = this;
      this.pendingComponentCb = cancellable(function (Component) {
        self.ComponentName = Component.options.name || (typeof value === 'string' ? value : null);
        self.Component = Component;
        cb();
      });
      this.vm._resolveComponent(value, this.pendingComponentCb);
    },

    /**
     * Create a new instance using the current constructor and
     * replace the existing instance. This method doesn't care
     * whether the new component and the old one are actually
     * the same.
     *
     * @param {Function} [cb]
     */

    mountComponent: function mountComponent(cb) {
      // actual mount
      this.unbuild(true);
      var self = this;
      var activateHooks = this.Component.options.activate;
      var cached = this.getCached();
      var newComponent = this.build();
      if (activateHooks && !cached) {
        this.waitingFor = newComponent;
        callActivateHooks(activateHooks, newComponent, function () {
          if (self.waitingFor !== newComponent) {
            return;
          }
          self.waitingFor = null;
          self.transition(newComponent, cb);
        });
      } else {
        // update ref for kept-alive component
        if (cached) {
          newComponent._updateRef();
        }
        this.transition(newComponent, cb);
      }
    },

    /**
     * When the component changes or unbinds before an async
     * constructor is resolved, we need to invalidate its
     * pending callback.
     */

    invalidatePending: function invalidatePending() {
      if (this.pendingComponentCb) {
        this.pendingComponentCb.cancel();
        this.pendingComponentCb = null;
      }
    },

    /**
     * Instantiate/insert a new child vm.
     * If keep alive and has cached instance, insert that
     * instance; otherwise build a new one and cache it.
     *
     * @param {Object} [extraOptions]
     * @return {Vue} - the created instance
     */

    build: function build(extraOptions) {
      var cached = this.getCached();
      if (cached) {
        return cached;
      }
      if (this.Component) {
        // default options
        var options = {
          name: this.ComponentName,
          el: cloneNode(this.el),
          template: this.inlineTemplate,
          // make sure to add the child with correct parent
          // if this is a transcluded component, its parent
          // should be the transclusion host.
          parent: this._host || this.vm,
          // if no inline-template, then the compiled
          // linker can be cached for better performance.
          _linkerCachable: !this.inlineTemplate,
          _ref: this.descriptor.ref,
          _asComponent: true,
          _isRouterView: this._isRouterView,
          // if this is a transcluded component, context
          // will be the common parent vm of this instance
          // and its host.
          _context: this.vm,
          // if this is inside an inline v-for, the scope
          // will be the intermediate scope created for this
          // repeat fragment. this is used for linking props
          // and container directives.
          _scope: this._scope,
          // pass in the owner fragment of this component.
          // this is necessary so that the fragment can keep
          // track of its contained components in order to
          // call attach/detach hooks for them.
          _frag: this._frag
        };
        // extra options
        // in 1.0.0 this is used by vue-router only
        /* istanbul ignore if */
        if (extraOptions) {
          extend(options, extraOptions);
        }
        var child = new this.Component(options);
        if (this.keepAlive) {
          this.cache[this.Component.cid] = child;
        }
        /* istanbul ignore if */
        if ('development' !== 'production' && this.el.hasAttribute('transition') && child._isFragment) {
          warn('Transitions will not work on a fragment instance. ' + 'Template: ' + child.$options.template, child);
        }
        return child;
      }
    },

    /**
     * Try to get a cached instance of the current component.
     *
     * @return {Vue|undefined}
     */

    getCached: function getCached() {
      return this.keepAlive && this.cache[this.Component.cid];
    },

    /**
     * Teardown the current child, but defers cleanup so
     * that we can separate the destroy and removal steps.
     *
     * @param {Boolean} defer
     */

    unbuild: function unbuild(defer) {
      if (this.waitingFor) {
        if (!this.keepAlive) {
          this.waitingFor.$destroy();
        }
        this.waitingFor = null;
      }
      var child = this.childVM;
      if (!child || this.keepAlive) {
        if (child) {
          // remove ref
          child._inactive = true;
          child._updateRef(true);
        }
        return;
      }
      // the sole purpose of `deferCleanup` is so that we can
      // "deactivate" the vm right now and perform DOM removal
      // later.
      child.$destroy(false, defer);
    },

    /**
     * Remove current destroyed child and manually do
     * the cleanup after removal.
     *
     * @param {Function} cb
     */

    remove: function remove(child, cb) {
      var keepAlive = this.keepAlive;
      if (child) {
        // we may have a component switch when a previous
        // component is still being transitioned out.
        // we want to trigger only one lastest insertion cb
        // when the existing transition finishes. (#1119)
        this.pendingRemovals++;
        this.pendingRemovalCb = cb;
        var self = this;
        child.$remove(function () {
          self.pendingRemovals--;
          if (!keepAlive) child._cleanup();
          if (!self.pendingRemovals && self.pendingRemovalCb) {
            self.pendingRemovalCb();
            self.pendingRemovalCb = null;
          }
        });
      } else if (cb) {
        cb();
      }
    },

    /**
     * Actually swap the components, depending on the
     * transition mode. Defaults to simultaneous.
     *
     * @param {Vue} target
     * @param {Function} [cb]
     */

    transition: function transition(target, cb) {
      var self = this;
      var current = this.childVM;
      // for devtool inspection
      if (current) current._inactive = true;
      target._inactive = false;
      this.childVM = target;
      switch (self.params.transitionMode) {
        case 'in-out':
          target.$before(self.anchor, function () {
            self.remove(current, cb);
          });
          break;
        case 'out-in':
          self.remove(current, function () {
            target.$before(self.anchor, cb);
          });
          break;
        default:
          self.remove(current);
          target.$before(self.anchor, cb);
      }
    },

    /**
     * Unbind.
     */

    unbind: function unbind() {
      this.invalidatePending();
      // Do not defer cleanup when unbinding
      this.unbuild();
      // destroy all keep-alive cached instances
      if (this.cache) {
        for (var key in this.cache) {
          this.cache[key].$destroy();
        }
        this.cache = null;
      }
    }
  };

  /**
   * Call activate hooks in order (asynchronous)
   *
   * @param {Array} hooks
   * @param {Vue} vm
   * @param {Function} cb
   */

  function callActivateHooks(hooks, vm, cb) {
    var total = hooks.length;
    var called = 0;
    hooks[0].call(vm, next);
    function next() {
      if (++called >= total) {
        cb();
      } else {
        hooks[called].call(vm, next);
      }
    }
  }

  var vClass = {

    deep: true,

    update: function update(value) {
      if (!value) {
        this.cleanup();
      } else if (typeof value === 'string') {
        this.setClass(value.trim().split(/\s+/));
      } else {
        this.setClass(normalize$1(value));
      }
    },

    setClass: function setClass(value) {
      this.cleanup(value);
      for (var i = 0, l = value.length; i < l; i++) {
        var val = value[i];
        if (val) {
          apply(this.el, val, addClass);
        }
      }
      this.prevKeys = value;
    },

    cleanup: function cleanup(value) {
      var prevKeys = this.prevKeys;
      if (!prevKeys) return;
      var i = prevKeys.length;
      while (i--) {
        var key = prevKeys[i];
        if (!value || value.indexOf(key) < 0) {
          apply(this.el, key, removeClass);
        }
      }
    }
  };

  /**
   * Normalize objects and arrays (potentially containing objects)
   * into array of strings.
   *
   * @param {Object|Array<String|Object>} value
   * @return {Array<String>}
   */

  function normalize$1(value) {
    var res = [];
    if (isArray(value)) {
      for (var i = 0, l = value.length; i < l; i++) {
        var _key = value[i];
        if (_key) {
          if (typeof _key === 'string') {
            res.push(_key);
          } else {
            for (var k in _key) {
              if (_key[k]) res.push(k);
            }
          }
        }
      }
    } else if (isObject(value)) {
      for (var key in value) {
        if (value[key]) res.push(key);
      }
    }
    return res;
  }

  /**
   * Add or remove a class/classes on an element
   *
   * @param {Element} el
   * @param {String} key The class name. This may or may not
   *                     contain a space character, in such a
   *                     case we'll deal with multiple class
   *                     names at once.
   * @param {Function} fn
   */

  function apply(el, key, fn) {
    key = key.trim();
    if (key.indexOf(' ') === -1) {
      fn(el, key);
      return;
    }
    // The key contains one or more space characters.
    // Since a class name doesn't accept such characters, we
    // treat it as multiple classes.
    var keys = key.split(/\s+/);
    for (var i = 0, l = keys.length; i < l; i++) {
      fn(el, keys[i]);
    }
  }

  var internalDirectives = {
    style: vStyle,
    'class': vClass,
    component: component,
    prop: propDef,
    transition: transition$1
  };

  // special binding prefixes
  var bindRE = /^v-bind:|^:/;
  var onRE = /^v-on:|^@/;
  var dirAttrRE = /^v-([^:]+)(?:$|:(.*)$)/;
  var modifierRE = /\.[^\.]+/g;
  var transitionRE = /^(v-bind:|:)?transition$/;

  // default directive priority
  var DEFAULT_PRIORITY = 1000;
  var DEFAULT_TERMINAL_PRIORITY = 2000;

  /**
   * Compile a template and return a reusable composite link
   * function, which recursively contains more link functions
   * inside. This top level compile function would normally
   * be called on instance root nodes, but can also be used
   * for partial compilation if the partial argument is true.
   *
   * The returned composite link function, when called, will
   * return an unlink function that tearsdown all directives
   * created during the linking phase.
   *
   * @param {Element|DocumentFragment} el
   * @param {Object} options
   * @param {Boolean} partial
   * @return {Function}
   */

  function compile(el, options, partial) {
    // link function for the node itself.
    var nodeLinkFn = partial || !options._asComponent ? compileNode(el, options) : null;
    // link function for the childNodes
    var childLinkFn = !(nodeLinkFn && nodeLinkFn.terminal) && !isScript(el) && el.hasChildNodes() ? compileNodeList(el.childNodes, options) : null;

    /**
     * A composite linker function to be called on a already
     * compiled piece of DOM, which instantiates all directive
     * instances.
     *
     * @param {Vue} vm
     * @param {Element|DocumentFragment} el
     * @param {Vue} [host] - host vm of transcluded content
     * @param {Object} [scope] - v-for scope
     * @param {Fragment} [frag] - link context fragment
     * @return {Function|undefined}
     */

    return function compositeLinkFn(vm, el, host, scope, frag) {
      // cache childNodes before linking parent, fix #657
      var childNodes = toArray(el.childNodes);
      // link
      var dirs = linkAndCapture(function compositeLinkCapturer() {
        if (nodeLinkFn) nodeLinkFn(vm, el, host, scope, frag);
        if (childLinkFn) childLinkFn(vm, childNodes, host, scope, frag);
      }, vm);
      return makeUnlinkFn(vm, dirs);
    };
  }

  /**
   * Apply a linker to a vm/element pair and capture the
   * directives created during the process.
   *
   * @param {Function} linker
   * @param {Vue} vm
   */

  function linkAndCapture(linker, vm) {
    /* istanbul ignore if */
    if ('development' === 'production') {}
    var originalDirCount = vm._directives.length;
    linker();
    var dirs = vm._directives.slice(originalDirCount);
    sortDirectives(dirs);
    for (var i = 0, l = dirs.length; i < l; i++) {
      dirs[i]._bind();
    }
    return dirs;
  }

  /**
   * sort directives by priority (stable sort)
   *
   * @param {Array} dirs
   */
  function sortDirectives(dirs) {
    if (dirs.length === 0) return;

    var groupedMap = {};
    var i, j, k, l;
    var index = 0;
    var priorities = [];
    for (i = 0, j = dirs.length; i < j; i++) {
      var dir = dirs[i];
      var priority = dir.descriptor.def.priority || DEFAULT_PRIORITY;
      var array = groupedMap[priority];
      if (!array) {
        array = groupedMap[priority] = [];
        priorities.push(priority);
      }
      array.push(dir);
    }

    priorities.sort(function (a, b) {
      return a > b ? -1 : a === b ? 0 : 1;
    });
    for (i = 0, j = priorities.length; i < j; i++) {
      var group = groupedMap[priorities[i]];
      for (k = 0, l = group.length; k < l; k++) {
        dirs[index++] = group[k];
      }
    }
  }

  /**
   * Linker functions return an unlink function that
   * tearsdown all directives instances generated during
   * the process.
   *
   * We create unlink functions with only the necessary
   * information to avoid retaining additional closures.
   *
   * @param {Vue} vm
   * @param {Array} dirs
   * @param {Vue} [context]
   * @param {Array} [contextDirs]
   * @return {Function}
   */

  function makeUnlinkFn(vm, dirs, context, contextDirs) {
    function unlink(destroying) {
      teardownDirs(vm, dirs, destroying);
      if (context && contextDirs) {
        teardownDirs(context, contextDirs);
      }
    }
    // expose linked directives
    unlink.dirs = dirs;
    return unlink;
  }

  /**
   * Teardown partial linked directives.
   *
   * @param {Vue} vm
   * @param {Array} dirs
   * @param {Boolean} destroying
   */

  function teardownDirs(vm, dirs, destroying) {
    var i = dirs.length;
    while (i--) {
      dirs[i]._teardown();
      if ('development' !== 'production' && !destroying) {
        vm._directives.$remove(dirs[i]);
      }
    }
  }

  /**
   * Compile link props on an instance.
   *
   * @param {Vue} vm
   * @param {Element} el
   * @param {Object} props
   * @param {Object} [scope]
   * @return {Function}
   */

  function compileAndLinkProps(vm, el, props, scope) {
    var propsLinkFn = compileProps(el, props, vm);
    var propDirs = linkAndCapture(function () {
      propsLinkFn(vm, scope);
    }, vm);
    return makeUnlinkFn(vm, propDirs);
  }

  /**
   * Compile the root element of an instance.
   *
   * 1. attrs on context container (context scope)
   * 2. attrs on the component template root node, if
   *    replace:true (child scope)
   *
   * If this is a fragment instance, we only need to compile 1.
   *
   * @param {Element} el
   * @param {Object} options
   * @param {Object} contextOptions
   * @return {Function}
   */

  function compileRoot(el, options, contextOptions) {
    var containerAttrs = options._containerAttrs;
    var replacerAttrs = options._replacerAttrs;
    var contextLinkFn, replacerLinkFn;

    // only need to compile other attributes for
    // non-fragment instances
    if (el.nodeType !== 11) {
      // for components, container and replacer need to be
      // compiled separately and linked in different scopes.
      if (options._asComponent) {
        // 2. container attributes
        if (containerAttrs && contextOptions) {
          contextLinkFn = compileDirectives(containerAttrs, contextOptions);
        }
        if (replacerAttrs) {
          // 3. replacer attributes
          replacerLinkFn = compileDirectives(replacerAttrs, options);
        }
      } else {
        // non-component, just compile as a normal element.
        replacerLinkFn = compileDirectives(el.attributes, options);
      }
    } else if ('development' !== 'production' && containerAttrs) {
      // warn container directives for fragment instances
      var names = containerAttrs.filter(function (attr) {
        // allow vue-loader/vueify scoped css attributes
        return attr.name.indexOf('_v-') < 0 &&
        // allow event listeners
        !onRE.test(attr.name) &&
        // allow slots
        attr.name !== 'slot';
      }).map(function (attr) {
        return '"' + attr.name + '"';
      });
      if (names.length) {
        var plural = names.length > 1;

        var componentName = options.el.tagName.toLowerCase();
        if (componentName === 'component' && options.name) {
          componentName += ':' + options.name;
        }

        warn('Attribute' + (plural ? 's ' : ' ') + names.join(', ') + (plural ? ' are' : ' is') + ' ignored on component ' + '<' + componentName + '> because ' + 'the component is a fragment instance: ' + 'http://vuejs.org/guide/components.html#Fragment-Instance');
      }
    }

    options._containerAttrs = options._replacerAttrs = null;
    return function rootLinkFn(vm, el, scope) {
      // link context scope dirs
      var context = vm._context;
      var contextDirs;
      if (context && contextLinkFn) {
        contextDirs = linkAndCapture(function () {
          contextLinkFn(context, el, null, scope);
        }, context);
      }

      // link self
      var selfDirs = linkAndCapture(function () {
        if (replacerLinkFn) replacerLinkFn(vm, el);
      }, vm);

      // return the unlink function that tearsdown context
      // container directives.
      return makeUnlinkFn(vm, selfDirs, context, contextDirs);
    };
  }

  /**
   * Compile a node and return a nodeLinkFn based on the
   * node type.
   *
   * @param {Node} node
   * @param {Object} options
   * @return {Function|null}
   */

  function compileNode(node, options) {
    var type = node.nodeType;
    if (type === 1 && !isScript(node)) {
      return compileElement(node, options);
    } else if (type === 3 && node.data.trim()) {
      return compileTextNode(node, options);
    } else {
      return null;
    }
  }

  /**
   * Compile an element and return a nodeLinkFn.
   *
   * @param {Element} el
   * @param {Object} options
   * @return {Function|null}
   */

  function compileElement(el, options) {
    // preprocess textareas.
    // textarea treats its text content as the initial value.
    // just bind it as an attr directive for value.
    if (el.tagName === 'TEXTAREA') {
      // a textarea which has v-pre attr should skip complie.
      if (getAttr(el, 'v-pre') !== null) {
        return skip;
      }
      var tokens = parseText(el.value);
      if (tokens) {
        el.setAttribute(':value', tokensToExp(tokens));
        el.value = '';
      }
    }
    var linkFn;
    var hasAttrs = el.hasAttributes();
    var attrs = hasAttrs && toArray(el.attributes);
    // check terminal directives (for & if)
    if (hasAttrs) {
      linkFn = checkTerminalDirectives(el, attrs, options);
    }
    // check element directives
    if (!linkFn) {
      linkFn = checkElementDirectives(el, options);
    }
    // check component
    if (!linkFn) {
      linkFn = checkComponent(el, options);
    }
    // normal directives
    if (!linkFn && hasAttrs) {
      linkFn = compileDirectives(attrs, options);
    }
    return linkFn;
  }

  /**
   * Compile a textNode and return a nodeLinkFn.
   *
   * @param {TextNode} node
   * @param {Object} options
   * @return {Function|null} textNodeLinkFn
   */

  function compileTextNode(node, options) {
    // skip marked text nodes
    if (node._skip) {
      return removeText;
    }

    var tokens = parseText(node.wholeText);
    if (!tokens) {
      return null;
    }

    // mark adjacent text nodes as skipped,
    // because we are using node.wholeText to compile
    // all adjacent text nodes together. This fixes
    // issues in IE where sometimes it splits up a single
    // text node into multiple ones.
    var next = node.nextSibling;
    while (next && next.nodeType === 3) {
      next._skip = true;
      next = next.nextSibling;
    }

    var frag = document.createDocumentFragment();
    var el, token;
    for (var i = 0, l = tokens.length; i < l; i++) {
      token = tokens[i];
      el = token.tag ? processTextToken(token, options) : document.createTextNode(token.value);
      frag.appendChild(el);
    }
    return makeTextNodeLinkFn(tokens, frag, options);
  }

  /**
   * Linker for an skipped text node.
   *
   * @param {Vue} vm
   * @param {Text} node
   */

  function removeText(vm, node) {
    remove(node);
  }

  /**
   * Process a single text token.
   *
   * @param {Object} token
   * @param {Object} options
   * @return {Node}
   */

  function processTextToken(token, options) {
    var el;
    if (token.oneTime) {
      el = document.createTextNode(token.value);
    } else {
      if (token.html) {
        el = document.createComment('v-html');
        setTokenType('html');
      } else {
        // IE will clean up empty textNodes during
        // frag.cloneNode(true), so we have to give it
        // something here...
        el = document.createTextNode(' ');
        setTokenType('text');
      }
    }
    function setTokenType(type) {
      if (token.descriptor) return;
      var parsed = parseDirective(token.value);
      token.descriptor = {
        name: type,
        def: publicDirectives[type],
        expression: parsed.expression,
        filters: parsed.filters
      };
    }
    return el;
  }

  /**
   * Build a function that processes a textNode.
   *
   * @param {Array<Object>} tokens
   * @param {DocumentFragment} frag
   */

  function makeTextNodeLinkFn(tokens, frag) {
    return function textNodeLinkFn(vm, el, host, scope) {
      var fragClone = frag.cloneNode(true);
      var childNodes = toArray(fragClone.childNodes);
      var token, value, node;
      for (var i = 0, l = tokens.length; i < l; i++) {
        token = tokens[i];
        value = token.value;
        if (token.tag) {
          node = childNodes[i];
          if (token.oneTime) {
            value = (scope || vm).$eval(value);
            if (token.html) {
              replace(node, parseTemplate(value, true));
            } else {
              node.data = _toString(value);
            }
          } else {
            vm._bindDir(token.descriptor, node, host, scope);
          }
        }
      }
      replace(el, fragClone);
    };
  }

  /**
   * Compile a node list and return a childLinkFn.
   *
   * @param {NodeList} nodeList
   * @param {Object} options
   * @return {Function|undefined}
   */

  function compileNodeList(nodeList, options) {
    var linkFns = [];
    var nodeLinkFn, childLinkFn, node;
    for (var i = 0, l = nodeList.length; i < l; i++) {
      node = nodeList[i];
      nodeLinkFn = compileNode(node, options);
      childLinkFn = !(nodeLinkFn && nodeLinkFn.terminal) && node.tagName !== 'SCRIPT' && node.hasChildNodes() ? compileNodeList(node.childNodes, options) : null;
      linkFns.push(nodeLinkFn, childLinkFn);
    }
    return linkFns.length ? makeChildLinkFn(linkFns) : null;
  }

  /**
   * Make a child link function for a node's childNodes.
   *
   * @param {Array<Function>} linkFns
   * @return {Function} childLinkFn
   */

  function makeChildLinkFn(linkFns) {
    return function childLinkFn(vm, nodes, host, scope, frag) {
      var node, nodeLinkFn, childrenLinkFn;
      for (var i = 0, n = 0, l = linkFns.length; i < l; n++) {
        node = nodes[n];
        nodeLinkFn = linkFns[i++];
        childrenLinkFn = linkFns[i++];
        // cache childNodes before linking parent, fix #657
        var childNodes = toArray(node.childNodes);
        if (nodeLinkFn) {
          nodeLinkFn(vm, node, host, scope, frag);
        }
        if (childrenLinkFn) {
          childrenLinkFn(vm, childNodes, host, scope, frag);
        }
      }
    };
  }

  /**
   * Check for element directives (custom elements that should
   * be resovled as terminal directives).
   *
   * @param {Element} el
   * @param {Object} options
   */

  function checkElementDirectives(el, options) {
    var tag = el.tagName.toLowerCase();
    if (commonTagRE.test(tag)) {
      return;
    }
    var def = resolveAsset(options, 'elementDirectives', tag);
    if (def) {
      return makeTerminalNodeLinkFn(el, tag, '', options, def);
    }
  }

  /**
   * Check if an element is a component. If yes, return
   * a component link function.
   *
   * @param {Element} el
   * @param {Object} options
   * @return {Function|undefined}
   */

  function checkComponent(el, options) {
    var component = checkComponentAttr(el, options);
    if (component) {
      var ref = findRef(el);
      var descriptor = {
        name: 'component',
        ref: ref,
        expression: component.id,
        def: internalDirectives.component,
        modifiers: {
          literal: !component.dynamic
        }
      };
      var componentLinkFn = function componentLinkFn(vm, el, host, scope, frag) {
        if (ref) {
          defineReactive((scope || vm).$refs, ref, null);
        }
        vm._bindDir(descriptor, el, host, scope, frag);
      };
      componentLinkFn.terminal = true;
      return componentLinkFn;
    }
  }

  /**
   * Check an element for terminal directives in fixed order.
   * If it finds one, return a terminal link function.
   *
   * @param {Element} el
   * @param {Array} attrs
   * @param {Object} options
   * @return {Function} terminalLinkFn
   */

  function checkTerminalDirectives(el, attrs, options) {
    // skip v-pre
    if (getAttr(el, 'v-pre') !== null) {
      return skip;
    }
    // skip v-else block, but only if following v-if
    if (el.hasAttribute('v-else')) {
      var prev = el.previousElementSibling;
      if (prev && prev.hasAttribute('v-if')) {
        return skip;
      }
    }

    var attr, name, value, modifiers, matched, dirName, rawName, arg, def, termDef;
    for (var i = 0, j = attrs.length; i < j; i++) {
      attr = attrs[i];
      name = attr.name.replace(modifierRE, '');
      if (matched = name.match(dirAttrRE)) {
        def = resolveAsset(options, 'directives', matched[1]);
        if (def && def.terminal) {
          if (!termDef || (def.priority || DEFAULT_TERMINAL_PRIORITY) > termDef.priority) {
            termDef = def;
            rawName = attr.name;
            modifiers = parseModifiers(attr.name);
            value = attr.value;
            dirName = matched[1];
            arg = matched[2];
          }
        }
      }
    }

    if (termDef) {
      return makeTerminalNodeLinkFn(el, dirName, value, options, termDef, rawName, arg, modifiers);
    }
  }

  function skip() {}
  skip.terminal = true;

  /**
   * Build a node link function for a terminal directive.
   * A terminal link function terminates the current
   * compilation recursion and handles compilation of the
   * subtree in the directive.
   *
   * @param {Element} el
   * @param {String} dirName
   * @param {String} value
   * @param {Object} options
   * @param {Object} def
   * @param {String} [rawName]
   * @param {String} [arg]
   * @param {Object} [modifiers]
   * @return {Function} terminalLinkFn
   */

  function makeTerminalNodeLinkFn(el, dirName, value, options, def, rawName, arg, modifiers) {
    var parsed = parseDirective(value);
    var descriptor = {
      name: dirName,
      arg: arg,
      expression: parsed.expression,
      filters: parsed.filters,
      raw: value,
      attr: rawName,
      modifiers: modifiers,
      def: def
    };
    // check ref for v-for, v-if and router-view
    if (dirName === 'for' || dirName === 'router-view') {
      descriptor.ref = findRef(el);
    }
    var fn = function terminalNodeLinkFn(vm, el, host, scope, frag) {
      if (descriptor.ref) {
        defineReactive((scope || vm).$refs, descriptor.ref, null);
      }
      vm._bindDir(descriptor, el, host, scope, frag);
    };
    fn.terminal = true;
    return fn;
  }

  /**
   * Compile the directives on an element and return a linker.
   *
   * @param {Array|NamedNodeMap} attrs
   * @param {Object} options
   * @return {Function}
   */

  function compileDirectives(attrs, options) {
    var i = attrs.length;
    var dirs = [];
    var attr, name, value, rawName, rawValue, dirName, arg, modifiers, dirDef, tokens, matched;
    while (i--) {
      attr = attrs[i];
      name = rawName = attr.name;
      value = rawValue = attr.value;
      tokens = parseText(value);
      // reset arg
      arg = null;
      // check modifiers
      modifiers = parseModifiers(name);
      name = name.replace(modifierRE, '');

      // attribute interpolations
      if (tokens) {
        value = tokensToExp(tokens);
        arg = name;
        pushDir('bind', publicDirectives.bind, tokens);
        // warn against mixing mustaches with v-bind
        if ('development' !== 'production') {
          if (name === 'class' && Array.prototype.some.call(attrs, function (attr) {
            return attr.name === ':class' || attr.name === 'v-bind:class';
          })) {
            warn('class="' + rawValue + '": Do not mix mustache interpolation ' + 'and v-bind for "class" on the same element. Use one or the other.', options);
          }
        }
      } else

        // special attribute: transition
        if (transitionRE.test(name)) {
          modifiers.literal = !bindRE.test(name);
          pushDir('transition', internalDirectives.transition);
        } else

          // event handlers
          if (onRE.test(name)) {
            arg = name.replace(onRE, '');
            pushDir('on', publicDirectives.on);
          } else

            // attribute bindings
            if (bindRE.test(name)) {
              dirName = name.replace(bindRE, '');
              if (dirName === 'style' || dirName === 'class') {
                pushDir(dirName, internalDirectives[dirName]);
              } else {
                arg = dirName;
                pushDir('bind', publicDirectives.bind);
              }
            } else

              // normal directives
              if (matched = name.match(dirAttrRE)) {
                dirName = matched[1];
                arg = matched[2];

                // skip v-else (when used with v-show)
                if (dirName === 'else') {
                  continue;
                }

                dirDef = resolveAsset(options, 'directives', dirName, true);
                if (dirDef) {
                  pushDir(dirName, dirDef);
                }
              }
    }

    /**
     * Push a directive.
     *
     * @param {String} dirName
     * @param {Object|Function} def
     * @param {Array} [interpTokens]
     */

    function pushDir(dirName, def, interpTokens) {
      var hasOneTimeToken = interpTokens && hasOneTime(interpTokens);
      var parsed = !hasOneTimeToken && parseDirective(value);
      dirs.push({
        name: dirName,
        attr: rawName,
        raw: rawValue,
        def: def,
        arg: arg,
        modifiers: modifiers,
        // conversion from interpolation strings with one-time token
        // to expression is differed until directive bind time so that we
        // have access to the actual vm context for one-time bindings.
        expression: parsed && parsed.expression,
        filters: parsed && parsed.filters,
        interp: interpTokens,
        hasOneTime: hasOneTimeToken
      });
    }

    if (dirs.length) {
      return makeNodeLinkFn(dirs);
    }
  }

  /**
   * Parse modifiers from directive attribute name.
   *
   * @param {String} name
   * @return {Object}
   */

  function parseModifiers(name) {
    var res = Object.create(null);
    var match = name.match(modifierRE);
    if (match) {
      var i = match.length;
      while (i--) {
        res[match[i].slice(1)] = true;
      }
    }
    return res;
  }

  /**
   * Build a link function for all directives on a single node.
   *
   * @param {Array} directives
   * @return {Function} directivesLinkFn
   */

  function makeNodeLinkFn(directives) {
    return function nodeLinkFn(vm, el, host, scope, frag) {
      // reverse apply because it's sorted low to high
      var i = directives.length;
      while (i--) {
        vm._bindDir(directives[i], el, host, scope, frag);
      }
    };
  }

  /**
   * Check if an interpolation string contains one-time tokens.
   *
   * @param {Array} tokens
   * @return {Boolean}
   */

  function hasOneTime(tokens) {
    var i = tokens.length;
    while (i--) {
      if (tokens[i].oneTime) return true;
    }
  }

  function isScript(el) {
    return el.tagName === 'SCRIPT' && (!el.hasAttribute('type') || el.getAttribute('type') === 'text/javascript');
  }

  var specialCharRE = /[^\w\-:\.]/;

  /**
   * Process an element or a DocumentFragment based on a
   * instance option object. This allows us to transclude
   * a template node/fragment before the instance is created,
   * so the processed fragment can then be cloned and reused
   * in v-for.
   *
   * @param {Element} el
   * @param {Object} options
   * @return {Element|DocumentFragment}
   */

  function transclude(el, options) {
    // extract container attributes to pass them down
    // to compiler, because they need to be compiled in
    // parent scope. we are mutating the options object here
    // assuming the same object will be used for compile
    // right after this.
    if (options) {
      options._containerAttrs = extractAttrs(el);
    }
    // for template tags, what we want is its content as
    // a documentFragment (for fragment instances)
    if (isTemplate(el)) {
      el = parseTemplate(el);
    }
    if (options) {
      if (options._asComponent && !options.template) {
        options.template = '<slot></slot>';
      }
      if (options.template) {
        options._content = extractContent(el);
        el = transcludeTemplate(el, options);
      }
    }
    if (isFragment(el)) {
      // anchors for fragment instance
      // passing in `persist: true` to avoid them being
      // discarded by IE during template cloning
      prepend(createAnchor('v-start', true), el);
      el.appendChild(createAnchor('v-end', true));
    }
    return el;
  }

  /**
   * Process the template option.
   * If the replace option is true this will swap the $el.
   *
   * @param {Element} el
   * @param {Object} options
   * @return {Element|DocumentFragment}
   */

  function transcludeTemplate(el, options) {
    var template = options.template;
    var frag = parseTemplate(template, true);
    if (frag) {
      var replacer = frag.firstChild;
      if (!replacer) {
        return frag;
      }
      var tag = replacer.tagName && replacer.tagName.toLowerCase();
      if (options.replace) {
        /* istanbul ignore if */
        if (el === document.body) {
          'development' !== 'production' && warn('You are mounting an instance with a template to ' + '<body>. This will replace <body> entirely. You ' + 'should probably use `replace: false` here.');
        }
        // there are many cases where the instance must
        // become a fragment instance: basically anything that
        // can create more than 1 root nodes.
        if (
        // multi-children template
        frag.childNodes.length > 1 ||
        // non-element template
        replacer.nodeType !== 1 ||
        // single nested component
        tag === 'component' || resolveAsset(options, 'components', tag) || hasBindAttr(replacer, 'is') ||
        // element directive
        resolveAsset(options, 'elementDirectives', tag) ||
        // for block
        replacer.hasAttribute('v-for') ||
        // if block
        replacer.hasAttribute('v-if')) {
          return frag;
        } else {
          options._replacerAttrs = extractAttrs(replacer);
          mergeAttrs(el, replacer);
          return replacer;
        }
      } else {
        el.appendChild(frag);
        return el;
      }
    } else {
      'development' !== 'production' && warn('Invalid template option: ' + template);
    }
  }

  /**
   * Helper to extract a component container's attributes
   * into a plain object array.
   *
   * @param {Element} el
   * @return {Array}
   */

  function extractAttrs(el) {
    if (el.nodeType === 1 && el.hasAttributes()) {
      return toArray(el.attributes);
    }
  }

  /**
   * Merge the attributes of two elements, and make sure
   * the class names are merged properly.
   *
   * @param {Element} from
   * @param {Element} to
   */

  function mergeAttrs(from, to) {
    var attrs = from.attributes;
    var i = attrs.length;
    var name, value;
    while (i--) {
      name = attrs[i].name;
      value = attrs[i].value;
      if (!to.hasAttribute(name) && !specialCharRE.test(name)) {
        to.setAttribute(name, value);
      } else if (name === 'class' && !parseText(value) && (value = value.trim())) {
        value.split(/\s+/).forEach(function (cls) {
          addClass(to, cls);
        });
      }
    }
  }

  /**
   * Scan and determine slot content distribution.
   * We do this during transclusion instead at compile time so that
   * the distribution is decoupled from the compilation order of
   * the slots.
   *
   * @param {Element|DocumentFragment} template
   * @param {Element} content
   * @param {Vue} vm
   */

  function resolveSlots(vm, content) {
    if (!content) {
      return;
    }
    var contents = vm._slotContents = Object.create(null);
    var el, name;
    for (var i = 0, l = content.children.length; i < l; i++) {
      el = content.children[i];
      /* eslint-disable no-cond-assign */
      if (name = el.getAttribute('slot')) {
        (contents[name] || (contents[name] = [])).push(el);
      }
      /* eslint-enable no-cond-assign */
      if ('development' !== 'production' && getBindAttr(el, 'slot')) {
        warn('The "slot" attribute must be static.', vm.$parent);
      }
    }
    for (name in contents) {
      contents[name] = extractFragment(contents[name], content);
    }
    if (content.hasChildNodes()) {
      var nodes = content.childNodes;
      if (nodes.length === 1 && nodes[0].nodeType === 3 && !nodes[0].data.trim()) {
        return;
      }
      contents['default'] = extractFragment(content.childNodes, content);
    }
  }

  /**
   * Extract qualified content nodes from a node list.
   *
   * @param {NodeList} nodes
   * @return {DocumentFragment}
   */

  function extractFragment(nodes, parent) {
    var frag = document.createDocumentFragment();
    nodes = toArray(nodes);
    for (var i = 0, l = nodes.length; i < l; i++) {
      var node = nodes[i];
      if (isTemplate(node) && !node.hasAttribute('v-if') && !node.hasAttribute('v-for')) {
        parent.removeChild(node);
        node = parseTemplate(node, true);
      }
      frag.appendChild(node);
    }
    return frag;
  }

  var compiler = Object.freeze({
  	compile: compile,
  	compileAndLinkProps: compileAndLinkProps,
  	compileRoot: compileRoot,
  	transclude: transclude,
  	resolveSlots: resolveSlots
  });

  function stateMixin (Vue) {
    /**
     * Accessor for `$data` property, since setting $data
     * requires observing the new object and updating
     * proxied properties.
     */

    Object.defineProperty(Vue.prototype, '$data', {
      get: function get() {
        return this._data;
      },
      set: function set(newData) {
        if (newData !== this._data) {
          this._setData(newData);
        }
      }
    });

    /**
     * Setup the scope of an instance, which contains:
     * - observed data
     * - computed properties
     * - user methods
     * - meta properties
     */

    Vue.prototype._initState = function () {
      this._initProps();
      this._initMeta();
      this._initMethods();
      this._initData();
      this._initComputed();
    };

    /**
     * Initialize props.
     */

    Vue.prototype._initProps = function () {
      var options = this.$options;
      var el = options.el;
      var props = options.props;
      if (props && !el) {
        'development' !== 'production' && warn('Props will not be compiled if no `el` option is ' + 'provided at instantiation.', this);
      }
      // make sure to convert string selectors into element now
      el = options.el = query(el);
      this._propsUnlinkFn = el && el.nodeType === 1 && props
      // props must be linked in proper scope if inside v-for
      ? compileAndLinkProps(this, el, props, this._scope) : null;
    };

    /**
     * Initialize the data.
     */

    Vue.prototype._initData = function () {
      var dataFn = this.$options.data;
      var data = this._data = dataFn ? dataFn() : {};
      if (!isPlainObject(data)) {
        data = {};
        'development' !== 'production' && warn('data functions should return an object.', this);
      }
      var props = this._props;
      // proxy data on instance
      var keys = Object.keys(data);
      var i, key;
      i = keys.length;
      while (i--) {
        key = keys[i];
        // there are two scenarios where we can proxy a data key:
        // 1. it's not already defined as a prop
        // 2. it's provided via a instantiation option AND there are no
        //    template prop present
        if (!props || !hasOwn(props, key)) {
          this._proxy(key);
        } else if ('development' !== 'production') {
          warn('Data field "' + key + '" is already defined ' + 'as a prop. To provide default value for a prop, use the "default" ' + 'prop option; if you want to pass prop values to an instantiation ' + 'call, use the "propsData" option.', this);
        }
      }
      // observe data
      observe(data, this);
    };

    /**
     * Swap the instance's $data. Called in $data's setter.
     *
     * @param {Object} newData
     */

    Vue.prototype._setData = function (newData) {
      newData = newData || {};
      var oldData = this._data;
      this._data = newData;
      var keys, key, i;
      // unproxy keys not present in new data
      keys = Object.keys(oldData);
      i = keys.length;
      while (i--) {
        key = keys[i];
        if (!(key in newData)) {
          this._unproxy(key);
        }
      }
      // proxy keys not already proxied,
      // and trigger change for changed values
      keys = Object.keys(newData);
      i = keys.length;
      while (i--) {
        key = keys[i];
        if (!hasOwn(this, key)) {
          // new property
          this._proxy(key);
        }
      }
      oldData.__ob__.removeVm(this);
      observe(newData, this);
      this._digest();
    };

    /**
     * Proxy a property, so that
     * vm.prop === vm._data.prop
     *
     * @param {String} key
     */

    Vue.prototype._proxy = function (key) {
      if (!isReserved(key)) {
        // need to store ref to self here
        // because these getter/setters might
        // be called by child scopes via
        // prototype inheritance.
        var self = this;
        Object.defineProperty(self, key, {
          configurable: true,
          enumerable: true,
          get: function proxyGetter() {
            return self._data[key];
          },
          set: function proxySetter(val) {
            self._data[key] = val;
          }
        });
      }
    };

    /**
     * Unproxy a property.
     *
     * @param {String} key
     */

    Vue.prototype._unproxy = function (key) {
      if (!isReserved(key)) {
        delete this[key];
      }
    };

    /**
     * Force update on every watcher in scope.
     */

    Vue.prototype._digest = function () {
      for (var i = 0, l = this._watchers.length; i < l; i++) {
        this._watchers[i].update(true); // shallow updates
      }
    };

    /**
     * Setup computed properties. They are essentially
     * special getter/setters
     */

    function noop() {}
    Vue.prototype._initComputed = function () {
      var computed = this.$options.computed;
      if (computed) {
        for (var key in computed) {
          var userDef = computed[key];
          var def = {
            enumerable: true,
            configurable: true
          };
          if (typeof userDef === 'function') {
            def.get = makeComputedGetter(userDef, this);
            def.set = noop;
          } else {
            def.get = userDef.get ? userDef.cache !== false ? makeComputedGetter(userDef.get, this) : bind(userDef.get, this) : noop;
            def.set = userDef.set ? bind(userDef.set, this) : noop;
          }
          Object.defineProperty(this, key, def);
        }
      }
    };

    function makeComputedGetter(getter, owner) {
      var watcher = new Watcher(owner, getter, null, {
        lazy: true
      });
      return function computedGetter() {
        if (watcher.dirty) {
          watcher.evaluate();
        }
        if (Dep.target) {
          watcher.depend();
        }
        return watcher.value;
      };
    }

    /**
     * Setup instance methods. Methods must be bound to the
     * instance since they might be passed down as a prop to
     * child components.
     */

    Vue.prototype._initMethods = function () {
      var methods = this.$options.methods;
      if (methods) {
        for (var key in methods) {
          this[key] = bind(methods[key], this);
        }
      }
    };

    /**
     * Initialize meta information like $index, $key & $value.
     */

    Vue.prototype._initMeta = function () {
      var metas = this.$options._meta;
      if (metas) {
        for (var key in metas) {
          defineReactive(this, key, metas[key]);
        }
      }
    };
  }

  var eventRE = /^v-on:|^@/;

  function eventsMixin (Vue) {
    /**
     * Setup the instance's option events & watchers.
     * If the value is a string, we pull it from the
     * instance's methods by name.
     */

    Vue.prototype._initEvents = function () {
      var options = this.$options;
      if (options._asComponent) {
        registerComponentEvents(this, options.el);
      }
      registerCallbacks(this, '$on', options.events);
      registerCallbacks(this, '$watch', options.watch);
    };

    /**
     * Register v-on events on a child component
     *
     * @param {Vue} vm
     * @param {Element} el
     */

    function registerComponentEvents(vm, el) {
      var attrs = el.attributes;
      var name, value, handler;
      for (var i = 0, l = attrs.length; i < l; i++) {
        name = attrs[i].name;
        if (eventRE.test(name)) {
          name = name.replace(eventRE, '');
          // force the expression into a statement so that
          // it always dynamically resolves the method to call (#2670)
          // kinda ugly hack, but does the job.
          value = attrs[i].value;
          if (isSimplePath(value)) {
            value += '.apply(this, $arguments)';
          }
          handler = (vm._scope || vm._context).$eval(value, true);
          handler._fromParent = true;
          vm.$on(name.replace(eventRE), handler);
        }
      }
    }

    /**
     * Register callbacks for option events and watchers.
     *
     * @param {Vue} vm
     * @param {String} action
     * @param {Object} hash
     */

    function registerCallbacks(vm, action, hash) {
      if (!hash) return;
      var handlers, key, i, j;
      for (key in hash) {
        handlers = hash[key];
        if (isArray(handlers)) {
          for (i = 0, j = handlers.length; i < j; i++) {
            register(vm, action, key, handlers[i]);
          }
        } else {
          register(vm, action, key, handlers);
        }
      }
    }

    /**
     * Helper to register an event/watch callback.
     *
     * @param {Vue} vm
     * @param {String} action
     * @param {String} key
     * @param {Function|String|Object} handler
     * @param {Object} [options]
     */

    function register(vm, action, key, handler, options) {
      var type = typeof handler;
      if (type === 'function') {
        vm[action](key, handler, options);
      } else if (type === 'string') {
        var methods = vm.$options.methods;
        var method = methods && methods[handler];
        if (method) {
          vm[action](key, method, options);
        } else {
          'development' !== 'production' && warn('Unknown method: "' + handler + '" when ' + 'registering callback for ' + action + ': "' + key + '".', vm);
        }
      } else if (handler && type === 'object') {
        register(vm, action, key, handler.handler, handler);
      }
    }

    /**
     * Setup recursive attached/detached calls
     */

    Vue.prototype._initDOMHooks = function () {
      this.$on('hook:attached', onAttached);
      this.$on('hook:detached', onDetached);
    };

    /**
     * Callback to recursively call attached hook on children
     */

    function onAttached() {
      if (!this._isAttached) {
        this._isAttached = true;
        this.$children.forEach(callAttach);
      }
    }

    /**
     * Iterator to call attached hook
     *
     * @param {Vue} child
     */

    function callAttach(child) {
      if (!child._isAttached && inDoc(child.$el)) {
        child._callHook('attached');
      }
    }

    /**
     * Callback to recursively call detached hook on children
     */

    function onDetached() {
      if (this._isAttached) {
        this._isAttached = false;
        this.$children.forEach(callDetach);
      }
    }

    /**
     * Iterator to call detached hook
     *
     * @param {Vue} child
     */

    function callDetach(child) {
      if (child._isAttached && !inDoc(child.$el)) {
        child._callHook('detached');
      }
    }

    /**
     * Trigger all handlers for a hook
     *
     * @param {String} hook
     */

    Vue.prototype._callHook = function (hook) {
      this.$emit('pre-hook:' + hook);
      var handlers = this.$options[hook];
      if (handlers) {
        for (var i = 0, j = handlers.length; i < j; i++) {
          handlers[i].call(this);
        }
      }
      this.$emit('hook:' + hook);
    };
  }

  function noop$1() {}

  /**
   * A directive links a DOM element with a piece of data,
   * which is the result of evaluating an expression.
   * It registers a watcher with the expression and calls
   * the DOM update function when a change is triggered.
   *
   * @param {Object} descriptor
   *                 - {String} name
   *                 - {Object} def
   *                 - {String} expression
   *                 - {Array<Object>} [filters]
   *                 - {Object} [modifiers]
   *                 - {Boolean} literal
   *                 - {String} attr
   *                 - {String} arg
   *                 - {String} raw
   *                 - {String} [ref]
   *                 - {Array<Object>} [interp]
   *                 - {Boolean} [hasOneTime]
   * @param {Vue} vm
   * @param {Node} el
   * @param {Vue} [host] - transclusion host component
   * @param {Object} [scope] - v-for scope
   * @param {Fragment} [frag] - owner fragment
   * @constructor
   */
  function Directive(descriptor, vm, el, host, scope, frag) {
    this.vm = vm;
    this.el = el;
    // copy descriptor properties
    this.descriptor = descriptor;
    this.name = descriptor.name;
    this.expression = descriptor.expression;
    this.arg = descriptor.arg;
    this.modifiers = descriptor.modifiers;
    this.filters = descriptor.filters;
    this.literal = this.modifiers && this.modifiers.literal;
    // private
    this._locked = false;
    this._bound = false;
    this._listeners = null;
    // link context
    this._host = host;
    this._scope = scope;
    this._frag = frag;
    // store directives on node in dev mode
    if ('development' !== 'production' && this.el) {
      this.el._vue_directives = this.el._vue_directives || [];
      this.el._vue_directives.push(this);
    }
  }

  /**
   * Initialize the directive, mixin definition properties,
   * setup the watcher, call definition bind() and update()
   * if present.
   */

  Directive.prototype._bind = function () {
    var name = this.name;
    var descriptor = this.descriptor;

    // remove attribute
    if ((name !== 'cloak' || this.vm._isCompiled) && this.el && this.el.removeAttribute) {
      var attr = descriptor.attr || 'v-' + name;
      this.el.removeAttribute(attr);
    }

    // copy def properties
    var def = descriptor.def;
    if (typeof def === 'function') {
      this.update = def;
    } else {
      extend(this, def);
    }

    // setup directive params
    this._setupParams();

    // initial bind
    if (this.bind) {
      this.bind();
    }
    this._bound = true;

    if (this.literal) {
      this.update && this.update(descriptor.raw);
    } else if ((this.expression || this.modifiers) && (this.update || this.twoWay) && !this._checkStatement()) {
      // wrapped updater for context
      var dir = this;
      if (this.update) {
        this._update = function (val, oldVal) {
          if (!dir._locked) {
            dir.update(val, oldVal);
          }
        };
      } else {
        this._update = noop$1;
      }
      var preProcess = this._preProcess ? bind(this._preProcess, this) : null;
      var postProcess = this._postProcess ? bind(this._postProcess, this) : null;
      var watcher = this._watcher = new Watcher(this.vm, this.expression, this._update, // callback
      {
        filters: this.filters,
        twoWay: this.twoWay,
        deep: this.deep,
        preProcess: preProcess,
        postProcess: postProcess,
        scope: this._scope
      });
      // v-model with inital inline value need to sync back to
      // model instead of update to DOM on init. They would
      // set the afterBind hook to indicate that.
      if (this.afterBind) {
        this.afterBind();
      } else if (this.update) {
        this.update(watcher.value);
      }
    }
  };

  /**
   * Setup all param attributes, e.g. track-by,
   * transition-mode, etc...
   */

  Directive.prototype._setupParams = function () {
    if (!this.params) {
      return;
    }
    var params = this.params;
    // swap the params array with a fresh object.
    this.params = Object.create(null);
    var i = params.length;
    var key, val, mappedKey;
    while (i--) {
      key = hyphenate(params[i]);
      mappedKey = camelize(key);
      val = getBindAttr(this.el, key);
      if (val != null) {
        // dynamic
        this._setupParamWatcher(mappedKey, val);
      } else {
        // static
        val = getAttr(this.el, key);
        if (val != null) {
          this.params[mappedKey] = val === '' ? true : val;
        }
      }
    }
  };

  /**
   * Setup a watcher for a dynamic param.
   *
   * @param {String} key
   * @param {String} expression
   */

  Directive.prototype._setupParamWatcher = function (key, expression) {
    var self = this;
    var called = false;
    var unwatch = (this._scope || this.vm).$watch(expression, function (val, oldVal) {
      self.params[key] = val;
      // since we are in immediate mode,
      // only call the param change callbacks if this is not the first update.
      if (called) {
        var cb = self.paramWatchers && self.paramWatchers[key];
        if (cb) {
          cb.call(self, val, oldVal);
        }
      } else {
        called = true;
      }
    }, {
      immediate: true,
      user: false
    });(this._paramUnwatchFns || (this._paramUnwatchFns = [])).push(unwatch);
  };

  /**
   * Check if the directive is a function caller
   * and if the expression is a callable one. If both true,
   * we wrap up the expression and use it as the event
   * handler.
   *
   * e.g. on-click="a++"
   *
   * @return {Boolean}
   */

  Directive.prototype._checkStatement = function () {
    var expression = this.expression;
    if (expression && this.acceptStatement && !isSimplePath(expression)) {
      var fn = parseExpression$1(expression).get;
      var scope = this._scope || this.vm;
      var handler = function handler(e) {
        scope.$event = e;
        fn.call(scope, scope);
        scope.$event = null;
      };
      if (this.filters) {
        handler = scope._applyFilters(handler, null, this.filters);
      }
      this.update(handler);
      return true;
    }
  };

  /**
   * Set the corresponding value with the setter.
   * This should only be used in two-way directives
   * e.g. v-model.
   *
   * @param {*} value
   * @public
   */

  Directive.prototype.set = function (value) {
    /* istanbul ignore else */
    if (this.twoWay) {
      this._withLock(function () {
        this._watcher.set(value);
      });
    } else if ('development' !== 'production') {
      warn('Directive.set() can only be used inside twoWay' + 'directives.');
    }
  };

  /**
   * Execute a function while preventing that function from
   * triggering updates on this directive instance.
   *
   * @param {Function} fn
   */

  Directive.prototype._withLock = function (fn) {
    var self = this;
    self._locked = true;
    fn.call(self);
    nextTick(function () {
      self._locked = false;
    });
  };

  /**
   * Convenience method that attaches a DOM event listener
   * to the directive element and autometically tears it down
   * during unbind.
   *
   * @param {String} event
   * @param {Function} handler
   * @param {Boolean} [useCapture]
   */

  Directive.prototype.on = function (event, handler, useCapture) {
    on(this.el, event, handler, useCapture);(this._listeners || (this._listeners = [])).push([event, handler]);
  };

  /**
   * Teardown the watcher and call unbind.
   */

  Directive.prototype._teardown = function () {
    if (this._bound) {
      this._bound = false;
      if (this.unbind) {
        this.unbind();
      }
      if (this._watcher) {
        this._watcher.teardown();
      }
      var listeners = this._listeners;
      var i;
      if (listeners) {
        i = listeners.length;
        while (i--) {
          off(this.el, listeners[i][0], listeners[i][1]);
        }
      }
      var unwatchFns = this._paramUnwatchFns;
      if (unwatchFns) {
        i = unwatchFns.length;
        while (i--) {
          unwatchFns[i]();
        }
      }
      if ('development' !== 'production' && this.el) {
        this.el._vue_directives.$remove(this);
      }
      this.vm = this.el = this._watcher = this._listeners = null;
    }
  };

  function lifecycleMixin (Vue) {
    /**
     * Update v-ref for component.
     *
     * @param {Boolean} remove
     */

    Vue.prototype._updateRef = function (remove) {
      var ref = this.$options._ref;
      if (ref) {
        var refs = (this._scope || this._context).$refs;
        if (remove) {
          if (refs[ref] === this) {
            refs[ref] = null;
          }
        } else {
          refs[ref] = this;
        }
      }
    };

    /**
     * Transclude, compile and link element.
     *
     * If a pre-compiled linker is available, that means the
     * passed in element will be pre-transcluded and compiled
     * as well - all we need to do is to call the linker.
     *
     * Otherwise we need to call transclude/compile/link here.
     *
     * @param {Element} el
     */

    Vue.prototype._compile = function (el) {
      var options = this.$options;

      // transclude and init element
      // transclude can potentially replace original
      // so we need to keep reference; this step also injects
      // the template and caches the original attributes
      // on the container node and replacer node.
      var original = el;
      el = transclude(el, options);
      this._initElement(el);

      // handle v-pre on root node (#2026)
      if (el.nodeType === 1 && getAttr(el, 'v-pre') !== null) {
        return;
      }

      // root is always compiled per-instance, because
      // container attrs and props can be different every time.
      var contextOptions = this._context && this._context.$options;
      var rootLinker = compileRoot(el, options, contextOptions);

      // resolve slot distribution
      resolveSlots(this, options._content);

      // compile and link the rest
      var contentLinkFn;
      var ctor = this.constructor;
      // component compilation can be cached
      // as long as it's not using inline-template
      if (options._linkerCachable) {
        contentLinkFn = ctor.linker;
        if (!contentLinkFn) {
          contentLinkFn = ctor.linker = compile(el, options);
        }
      }

      // link phase
      // make sure to link root with prop scope!
      var rootUnlinkFn = rootLinker(this, el, this._scope);
      var contentUnlinkFn = contentLinkFn ? contentLinkFn(this, el) : compile(el, options)(this, el);

      // register composite unlink function
      // to be called during instance destruction
      this._unlinkFn = function () {
        rootUnlinkFn();
        // passing destroying: true to avoid searching and
        // splicing the directives
        contentUnlinkFn(true);
      };

      // finally replace original
      if (options.replace) {
        replace(original, el);
      }

      this._isCompiled = true;
      this._callHook('compiled');
    };

    /**
     * Initialize instance element. Called in the public
     * $mount() method.
     *
     * @param {Element} el
     */

    Vue.prototype._initElement = function (el) {
      if (isFragment(el)) {
        this._isFragment = true;
        this.$el = this._fragmentStart = el.firstChild;
        this._fragmentEnd = el.lastChild;
        // set persisted text anchors to empty
        if (this._fragmentStart.nodeType === 3) {
          this._fragmentStart.data = this._fragmentEnd.data = '';
        }
        this._fragment = el;
      } else {
        this.$el = el;
      }
      this.$el.__vue__ = this;
      this._callHook('beforeCompile');
    };

    /**
     * Create and bind a directive to an element.
     *
     * @param {Object} descriptor - parsed directive descriptor
     * @param {Node} node   - target node
     * @param {Vue} [host] - transclusion host component
     * @param {Object} [scope] - v-for scope
     * @param {Fragment} [frag] - owner fragment
     */

    Vue.prototype._bindDir = function (descriptor, node, host, scope, frag) {
      this._directives.push(new Directive(descriptor, this, node, host, scope, frag));
    };

    /**
     * Teardown an instance, unobserves the data, unbind all the
     * directives, turn off all the event listeners, etc.
     *
     * @param {Boolean} remove - whether to remove the DOM node.
     * @param {Boolean} deferCleanup - if true, defer cleanup to
     *                                 be called later
     */

    Vue.prototype._destroy = function (remove, deferCleanup) {
      if (this._isBeingDestroyed) {
        if (!deferCleanup) {
          this._cleanup();
        }
        return;
      }

      var destroyReady;
      var pendingRemoval;

      var self = this;
      // Cleanup should be called either synchronously or asynchronoysly as
      // callback of this.$remove(), or if remove and deferCleanup are false.
      // In any case it should be called after all other removing, unbinding and
      // turning of is done
      var cleanupIfPossible = function cleanupIfPossible() {
        if (destroyReady && !pendingRemoval && !deferCleanup) {
          self._cleanup();
        }
      };

      // remove DOM element
      if (remove && this.$el) {
        pendingRemoval = true;
        this.$remove(function () {
          pendingRemoval = false;
          cleanupIfPossible();
        });
      }

      this._callHook('beforeDestroy');
      this._isBeingDestroyed = true;
      var i;
      // remove self from parent. only necessary
      // if parent is not being destroyed as well.
      var parent = this.$parent;
      if (parent && !parent._isBeingDestroyed) {
        parent.$children.$remove(this);
        // unregister ref (remove: true)
        this._updateRef(true);
      }
      // destroy all children.
      i = this.$children.length;
      while (i--) {
        this.$children[i].$destroy();
      }
      // teardown props
      if (this._propsUnlinkFn) {
        this._propsUnlinkFn();
      }
      // teardown all directives. this also tearsdown all
      // directive-owned watchers.
      if (this._unlinkFn) {
        this._unlinkFn();
      }
      i = this._watchers.length;
      while (i--) {
        this._watchers[i].teardown();
      }
      // remove reference to self on $el
      if (this.$el) {
        this.$el.__vue__ = null;
      }

      destroyReady = true;
      cleanupIfPossible();
    };

    /**
     * Clean up to ensure garbage collection.
     * This is called after the leave transition if there
     * is any.
     */

    Vue.prototype._cleanup = function () {
      if (this._isDestroyed) {
        return;
      }
      // remove self from owner fragment
      // do it in cleanup so that we can call $destroy with
      // defer right when a fragment is about to be removed.
      if (this._frag) {
        this._frag.children.$remove(this);
      }
      // remove reference from data ob
      // frozen object may not have observer.
      if (this._data && this._data.__ob__) {
        this._data.__ob__.removeVm(this);
      }
      // Clean up references to private properties and other
      // instances. preserve reference to _data so that proxy
      // accessors still work. The only potential side effect
      // here is that mutating the instance after it's destroyed
      // may affect the state of other components that are still
      // observing the same object, but that seems to be a
      // reasonable responsibility for the user rather than
      // always throwing an error on them.
      this.$el = this.$parent = this.$root = this.$children = this._watchers = this._context = this._scope = this._directives = null;
      // call the last hook...
      this._isDestroyed = true;
      this._callHook('destroyed');
      // turn off all instance listeners.
      this.$off();
    };
  }

  function miscMixin (Vue) {
    /**
     * Apply a list of filter (descriptors) to a value.
     * Using plain for loops here because this will be called in
     * the getter of any watcher with filters so it is very
     * performance sensitive.
     *
     * @param {*} value
     * @param {*} [oldValue]
     * @param {Array} filters
     * @param {Boolean} write
     * @return {*}
     */

    Vue.prototype._applyFilters = function (value, oldValue, filters, write) {
      var filter, fn, args, arg, offset, i, l, j, k;
      for (i = 0, l = filters.length; i < l; i++) {
        filter = filters[write ? l - i - 1 : i];
        fn = resolveAsset(this.$options, 'filters', filter.name, true);
        if (!fn) continue;
        fn = write ? fn.write : fn.read || fn;
        if (typeof fn !== 'function') continue;
        args = write ? [value, oldValue] : [value];
        offset = write ? 2 : 1;
        if (filter.args) {
          for (j = 0, k = filter.args.length; j < k; j++) {
            arg = filter.args[j];
            args[j + offset] = arg.dynamic ? this.$get(arg.value) : arg.value;
          }
        }
        value = fn.apply(this, args);
      }
      return value;
    };

    /**
     * Resolve a component, depending on whether the component
     * is defined normally or using an async factory function.
     * Resolves synchronously if already resolved, otherwise
     * resolves asynchronously and caches the resolved
     * constructor on the factory.
     *
     * @param {String|Function} value
     * @param {Function} cb
     */

    Vue.prototype._resolveComponent = function (value, cb) {
      var factory;
      if (typeof value === 'function') {
        factory = value;
      } else {
        factory = resolveAsset(this.$options, 'components', value, true);
      }
      /* istanbul ignore if */
      if (!factory) {
        return;
      }
      // async component factory
      if (!factory.options) {
        if (factory.resolved) {
          // cached
          cb(factory.resolved);
        } else if (factory.requested) {
          // pool callbacks
          factory.pendingCallbacks.push(cb);
        } else {
          factory.requested = true;
          var cbs = factory.pendingCallbacks = [cb];
          factory.call(this, function resolve(res) {
            if (isPlainObject(res)) {
              res = Vue.extend(res);
            }
            // cache resolved
            factory.resolved = res;
            // invoke callbacks
            for (var i = 0, l = cbs.length; i < l; i++) {
              cbs[i](res);
            }
          }, function reject(reason) {
            'development' !== 'production' && warn('Failed to resolve async component' + (typeof value === 'string' ? ': ' + value : '') + '. ' + (reason ? '\nReason: ' + reason : ''));
          });
        }
      } else {
        // normal component
        cb(factory);
      }
    };
  }

  var filterRE = /[^|]\|[^|]/;

  function dataAPI (Vue) {
    /**
     * Get the value from an expression on this vm.
     *
     * @param {String} exp
     * @param {Boolean} [asStatement]
     * @return {*}
     */

    Vue.prototype.$get = function (exp, asStatement) {
      var res = parseExpression$1(exp);
      if (res) {
        if (asStatement) {
          var self = this;
          return function statementHandler() {
            self.$arguments = toArray(arguments);
            var result = res.get.call(self, self);
            self.$arguments = null;
            return result;
          };
        } else {
          try {
            return res.get.call(this, this);
          } catch (e) {}
        }
      }
    };

    /**
     * Set the value from an expression on this vm.
     * The expression must be a valid left-hand
     * expression in an assignment.
     *
     * @param {String} exp
     * @param {*} val
     */

    Vue.prototype.$set = function (exp, val) {
      var res = parseExpression$1(exp, true);
      if (res && res.set) {
        res.set.call(this, this, val);
      }
    };

    /**
     * Delete a property on the VM
     *
     * @param {String} key
     */

    Vue.prototype.$delete = function (key) {
      del(this._data, key);
    };

    /**
     * Watch an expression, trigger callback when its
     * value changes.
     *
     * @param {String|Function} expOrFn
     * @param {Function} cb
     * @param {Object} [options]
     *                 - {Boolean} deep
     *                 - {Boolean} immediate
     * @return {Function} - unwatchFn
     */

    Vue.prototype.$watch = function (expOrFn, cb, options) {
      var vm = this;
      var parsed;
      if (typeof expOrFn === 'string') {
        parsed = parseDirective(expOrFn);
        expOrFn = parsed.expression;
      }
      var watcher = new Watcher(vm, expOrFn, cb, {
        deep: options && options.deep,
        sync: options && options.sync,
        filters: parsed && parsed.filters,
        user: !options || options.user !== false
      });
      if (options && options.immediate) {
        cb.call(vm, watcher.value);
      }
      return function unwatchFn() {
        watcher.teardown();
      };
    };

    /**
     * Evaluate a text directive, including filters.
     *
     * @param {String} text
     * @param {Boolean} [asStatement]
     * @return {String}
     */

    Vue.prototype.$eval = function (text, asStatement) {
      // check for filters.
      if (filterRE.test(text)) {
        var dir = parseDirective(text);
        // the filter regex check might give false positive
        // for pipes inside strings, so it's possible that
        // we don't get any filters here
        var val = this.$get(dir.expression, asStatement);
        return dir.filters ? this._applyFilters(val, null, dir.filters) : val;
      } else {
        // no filter
        return this.$get(text, asStatement);
      }
    };

    /**
     * Interpolate a piece of template text.
     *
     * @param {String} text
     * @return {String}
     */

    Vue.prototype.$interpolate = function (text) {
      var tokens = parseText(text);
      var vm = this;
      if (tokens) {
        if (tokens.length === 1) {
          return vm.$eval(tokens[0].value) + '';
        } else {
          return tokens.map(function (token) {
            return token.tag ? vm.$eval(token.value) : token.value;
          }).join('');
        }
      } else {
        return text;
      }
    };

    /**
     * Log instance data as a plain JS object
     * so that it is easier to inspect in console.
     * This method assumes console is available.
     *
     * @param {String} [path]
     */

    Vue.prototype.$log = function (path) {
      var data = path ? getPath(this._data, path) : this._data;
      if (data) {
        data = clean(data);
      }
      // include computed fields
      if (!path) {
        var key;
        for (key in this.$options.computed) {
          data[key] = clean(this[key]);
        }
        if (this._props) {
          for (key in this._props) {
            data[key] = clean(this[key]);
          }
        }
      }
      console.log(data);
    };

    /**
     * "clean" a getter/setter converted object into a plain
     * object copy.
     *
     * @param {Object} - obj
     * @return {Object}
     */

    function clean(obj) {
      return JSON.parse(JSON.stringify(obj));
    }
  }

  function domAPI (Vue) {
    /**
     * Convenience on-instance nextTick. The callback is
     * auto-bound to the instance, and this avoids component
     * modules having to rely on the global Vue.
     *
     * @param {Function} fn
     */

    Vue.prototype.$nextTick = function (fn) {
      nextTick(fn, this);
    };

    /**
     * Append instance to target
     *
     * @param {Node} target
     * @param {Function} [cb]
     * @param {Boolean} [withTransition] - defaults to true
     */

    Vue.prototype.$appendTo = function (target, cb, withTransition) {
      return insert(this, target, cb, withTransition, append, appendWithTransition);
    };

    /**
     * Prepend instance to target
     *
     * @param {Node} target
     * @param {Function} [cb]
     * @param {Boolean} [withTransition] - defaults to true
     */

    Vue.prototype.$prependTo = function (target, cb, withTransition) {
      target = query(target);
      if (target.hasChildNodes()) {
        this.$before(target.firstChild, cb, withTransition);
      } else {
        this.$appendTo(target, cb, withTransition);
      }
      return this;
    };

    /**
     * Insert instance before target
     *
     * @param {Node} target
     * @param {Function} [cb]
     * @param {Boolean} [withTransition] - defaults to true
     */

    Vue.prototype.$before = function (target, cb, withTransition) {
      return insert(this, target, cb, withTransition, beforeWithCb, beforeWithTransition);
    };

    /**
     * Insert instance after target
     *
     * @param {Node} target
     * @param {Function} [cb]
     * @param {Boolean} [withTransition] - defaults to true
     */

    Vue.prototype.$after = function (target, cb, withTransition) {
      target = query(target);
      if (target.nextSibling) {
        this.$before(target.nextSibling, cb, withTransition);
      } else {
        this.$appendTo(target.parentNode, cb, withTransition);
      }
      return this;
    };

    /**
     * Remove instance from DOM
     *
     * @param {Function} [cb]
     * @param {Boolean} [withTransition] - defaults to true
     */

    Vue.prototype.$remove = function (cb, withTransition) {
      if (!this.$el.parentNode) {
        return cb && cb();
      }
      var inDocument = this._isAttached && inDoc(this.$el);
      // if we are not in document, no need to check
      // for transitions
      if (!inDocument) withTransition = false;
      var self = this;
      var realCb = function realCb() {
        if (inDocument) self._callHook('detached');
        if (cb) cb();
      };
      if (this._isFragment) {
        removeNodeRange(this._fragmentStart, this._fragmentEnd, this, this._fragment, realCb);
      } else {
        var op = withTransition === false ? removeWithCb : removeWithTransition;
        op(this.$el, this, realCb);
      }
      return this;
    };

    /**
     * Shared DOM insertion function.
     *
     * @param {Vue} vm
     * @param {Element} target
     * @param {Function} [cb]
     * @param {Boolean} [withTransition]
     * @param {Function} op1 - op for non-transition insert
     * @param {Function} op2 - op for transition insert
     * @return vm
     */

    function insert(vm, target, cb, withTransition, op1, op2) {
      target = query(target);
      var targetIsDetached = !inDoc(target);
      var op = withTransition === false || targetIsDetached ? op1 : op2;
      var shouldCallHook = !targetIsDetached && !vm._isAttached && !inDoc(vm.$el);
      if (vm._isFragment) {
        mapNodeRange(vm._fragmentStart, vm._fragmentEnd, function (node) {
          op(node, target, vm);
        });
        cb && cb();
      } else {
        op(vm.$el, target, vm, cb);
      }
      if (shouldCallHook) {
        vm._callHook('attached');
      }
      return vm;
    }

    /**
     * Check for selectors
     *
     * @param {String|Element} el
     */

    function query(el) {
      return typeof el === 'string' ? document.querySelector(el) : el;
    }

    /**
     * Append operation that takes a callback.
     *
     * @param {Node} el
     * @param {Node} target
     * @param {Vue} vm - unused
     * @param {Function} [cb]
     */

    function append(el, target, vm, cb) {
      target.appendChild(el);
      if (cb) cb();
    }

    /**
     * InsertBefore operation that takes a callback.
     *
     * @param {Node} el
     * @param {Node} target
     * @param {Vue} vm - unused
     * @param {Function} [cb]
     */

    function beforeWithCb(el, target, vm, cb) {
      before(el, target);
      if (cb) cb();
    }

    /**
     * Remove operation that takes a callback.
     *
     * @param {Node} el
     * @param {Vue} vm - unused
     * @param {Function} [cb]
     */

    function removeWithCb(el, vm, cb) {
      remove(el);
      if (cb) cb();
    }
  }

  function eventsAPI (Vue) {
    /**
     * Listen on the given `event` with `fn`.
     *
     * @param {String} event
     * @param {Function} fn
     */

    Vue.prototype.$on = function (event, fn) {
      (this._events[event] || (this._events[event] = [])).push(fn);
      modifyListenerCount(this, event, 1);
      return this;
    };

    /**
     * Adds an `event` listener that will be invoked a single
     * time then automatically removed.
     *
     * @param {String} event
     * @param {Function} fn
     */

    Vue.prototype.$once = function (event, fn) {
      var self = this;
      function on() {
        self.$off(event, on);
        fn.apply(this, arguments);
      }
      on.fn = fn;
      this.$on(event, on);
      return this;
    };

    /**
     * Remove the given callback for `event` or all
     * registered callbacks.
     *
     * @param {String} event
     * @param {Function} fn
     */

    Vue.prototype.$off = function (event, fn) {
      var cbs;
      // all
      if (!arguments.length) {
        if (this.$parent) {
          for (event in this._events) {
            cbs = this._events[event];
            if (cbs) {
              modifyListenerCount(this, event, -cbs.length);
            }
          }
        }
        this._events = {};
        return this;
      }
      // specific event
      cbs = this._events[event];
      if (!cbs) {
        return this;
      }
      if (arguments.length === 1) {
        modifyListenerCount(this, event, -cbs.length);
        this._events[event] = null;
        return this;
      }
      // specific handler
      var cb;
      var i = cbs.length;
      while (i--) {
        cb = cbs[i];
        if (cb === fn || cb.fn === fn) {
          modifyListenerCount(this, event, -1);
          cbs.splice(i, 1);
          break;
        }
      }
      return this;
    };

    /**
     * Trigger an event on self.
     *
     * @param {String|Object} event
     * @return {Boolean} shouldPropagate
     */

    Vue.prototype.$emit = function (event) {
      var isSource = typeof event === 'string';
      event = isSource ? event : event.name;
      var cbs = this._events[event];
      var shouldPropagate = isSource || !cbs;
      if (cbs) {
        cbs = cbs.length > 1 ? toArray(cbs) : cbs;
        // this is a somewhat hacky solution to the question raised
        // in #2102: for an inline component listener like <comp @test="doThis">,
        // the propagation handling is somewhat broken. Therefore we
        // need to treat these inline callbacks differently.
        var hasParentCbs = isSource && cbs.some(function (cb) {
          return cb._fromParent;
        });
        if (hasParentCbs) {
          shouldPropagate = false;
        }
        var args = toArray(arguments, 1);
        for (var i = 0, l = cbs.length; i < l; i++) {
          var cb = cbs[i];
          var res = cb.apply(this, args);
          if (res === true && (!hasParentCbs || cb._fromParent)) {
            shouldPropagate = true;
          }
        }
      }
      return shouldPropagate;
    };

    /**
     * Recursively broadcast an event to all children instances.
     *
     * @param {String|Object} event
     * @param {...*} additional arguments
     */

    Vue.prototype.$broadcast = function (event) {
      var isSource = typeof event === 'string';
      event = isSource ? event : event.name;
      // if no child has registered for this event,
      // then there's no need to broadcast.
      if (!this._eventsCount[event]) return;
      var children = this.$children;
      var args = toArray(arguments);
      if (isSource) {
        // use object event to indicate non-source emit
        // on children
        args[0] = { name: event, source: this };
      }
      for (var i = 0, l = children.length; i < l; i++) {
        var child = children[i];
        var shouldPropagate = child.$emit.apply(child, args);
        if (shouldPropagate) {
          child.$broadcast.apply(child, args);
        }
      }
      return this;
    };

    /**
     * Recursively propagate an event up the parent chain.
     *
     * @param {String} event
     * @param {...*} additional arguments
     */

    Vue.prototype.$dispatch = function (event) {
      var shouldPropagate = this.$emit.apply(this, arguments);
      if (!shouldPropagate) return;
      var parent = this.$parent;
      var args = toArray(arguments);
      // use object event to indicate non-source emit
      // on parents
      args[0] = { name: event, source: this };
      while (parent) {
        shouldPropagate = parent.$emit.apply(parent, args);
        parent = shouldPropagate ? parent.$parent : null;
      }
      return this;
    };

    /**
     * Modify the listener counts on all parents.
     * This bookkeeping allows $broadcast to return early when
     * no child has listened to a certain event.
     *
     * @param {Vue} vm
     * @param {String} event
     * @param {Number} count
     */

    var hookRE = /^hook:/;
    function modifyListenerCount(vm, event, count) {
      var parent = vm.$parent;
      // hooks do not get broadcasted so no need
      // to do bookkeeping for them
      if (!parent || !count || hookRE.test(event)) return;
      while (parent) {
        parent._eventsCount[event] = (parent._eventsCount[event] || 0) + count;
        parent = parent.$parent;
      }
    }
  }

  function lifecycleAPI (Vue) {
    /**
     * Set instance target element and kick off the compilation
     * process. The passed in `el` can be a selector string, an
     * existing Element, or a DocumentFragment (for block
     * instances).
     *
     * @param {Element|DocumentFragment|string} el
     * @public
     */

    Vue.prototype.$mount = function (el) {
      if (this._isCompiled) {
        'development' !== 'production' && warn('$mount() should be called only once.', this);
        return;
      }
      el = query(el);
      if (!el) {
        el = document.createElement('div');
      }
      this._compile(el);
      this._initDOMHooks();
      if (inDoc(this.$el)) {
        this._callHook('attached');
        ready.call(this);
      } else {
        this.$once('hook:attached', ready);
      }
      return this;
    };

    /**
     * Mark an instance as ready.
     */

    function ready() {
      this._isAttached = true;
      this._isReady = true;
      this._callHook('ready');
    }

    /**
     * Teardown the instance, simply delegate to the internal
     * _destroy.
     *
     * @param {Boolean} remove
     * @param {Boolean} deferCleanup
     */

    Vue.prototype.$destroy = function (remove, deferCleanup) {
      this._destroy(remove, deferCleanup);
    };

    /**
     * Partially compile a piece of DOM and return a
     * decompile function.
     *
     * @param {Element|DocumentFragment} el
     * @param {Vue} [host]
     * @param {Object} [scope]
     * @param {Fragment} [frag]
     * @return {Function}
     */

    Vue.prototype.$compile = function (el, host, scope, frag) {
      return compile(el, this.$options, true)(this, el, host, scope, frag);
    };
  }

  /**
   * The exposed Vue constructor.
   *
   * API conventions:
   * - public API methods/properties are prefixed with `$`
   * - internal methods/properties are prefixed with `_`
   * - non-prefixed properties are assumed to be proxied user
   *   data.
   *
   * @constructor
   * @param {Object} [options]
   * @public
   */

  function Vue(options) {
    this._init(options);
  }

  // install internals
  initMixin(Vue);
  stateMixin(Vue);
  eventsMixin(Vue);
  lifecycleMixin(Vue);
  miscMixin(Vue);

  // install instance APIs
  dataAPI(Vue);
  domAPI(Vue);
  eventsAPI(Vue);
  lifecycleAPI(Vue);

  var commonTagRE = /^(div|p|span|img|a|b|i|br|ul|ol|li|h1|h2|h3|h4|h5|h6|code|pre|table|th|td|tr|form|label|input|select|option|nav|article|section|header|footer)$/i;
  var reservedTagRE = /^(slot|partial|component)$/i;

  var isUnknownElement = undefined;
  if ('development' !== 'production') {
    isUnknownElement = function (el, tag) {
      if (tag.indexOf('-') > -1) {
        // http://stackoverflow.com/a/28210364/1070244
        return el.constructor === window.HTMLUnknownElement || el.constructor === window.HTMLElement;
      } else {
        return (/HTMLUnknownElement/.test(el.toString()) &&
          // Chrome returns unknown for several HTML5 elements.
          // https://code.google.com/p/chromium/issues/detail?id=540526
          // Firefox returns unknown for some "Interactive elements."
          !/^(data|time|rtc|rb|details|dialog|summary)$/.test(tag)
        );
      }
    };
  }

  /**
   * Check if an element is a component, if yes return its
   * component id.
   *
   * @param {Element} el
   * @param {Object} options
   * @return {Object|undefined}
   */

  function checkComponentAttr(el, options) {
    var tag = el.tagName.toLowerCase();
    var hasAttrs = el.hasAttributes();
    if (!commonTagRE.test(tag) && !reservedTagRE.test(tag)) {
      if (resolveAsset(options, 'components', tag)) {
        return { id: tag };
      } else {
        var is = hasAttrs && getIsBinding(el, options);
        if (is) {
          return is;
        } else if ('development' !== 'production') {
          var expectedTag = options._componentNameMap && options._componentNameMap[tag];
          if (expectedTag) {
            warn('Unknown custom element: <' + tag + '> - ' + 'did you mean <' + expectedTag + '>? ' + 'HTML is case-insensitive, remember to use kebab-case in templates.');
          } else if (isUnknownElement(el, tag)) {
            warn('Unknown custom element: <' + tag + '> - did you ' + 'register the component correctly? For recursive components, ' + 'make sure to provide the "name" option.');
          }
        }
      }
    } else if (hasAttrs) {
      return getIsBinding(el, options);
    }
  }

  /**
   * Get "is" binding from an element.
   *
   * @param {Element} el
   * @param {Object} options
   * @return {Object|undefined}
   */

  function getIsBinding(el, options) {
    // dynamic syntax
    var exp = el.getAttribute('is');
    if (exp != null) {
      if (resolveAsset(options, 'components', exp)) {
        el.removeAttribute('is');
        return { id: exp };
      }
    } else {
      exp = getBindAttr(el, 'is');
      if (exp != null) {
        return { id: exp, dynamic: true };
      }
    }
  }

  /**
   * Option overwriting strategies are functions that handle
   * how to merge a parent option value and a child option
   * value into the final value.
   *
   * All strategy functions follow the same signature:
   *
   * @param {*} parentVal
   * @param {*} childVal
   * @param {Vue} [vm]
   */

  var strats = config.optionMergeStrategies = Object.create(null);

  /**
   * Helper that recursively merges two data objects together.
   */

  function mergeData(to, from) {
    var key, toVal, fromVal;
    for (key in from) {
      toVal = to[key];
      fromVal = from[key];
      if (!hasOwn(to, key)) {
        set(to, key, fromVal);
      } else if (isObject(toVal) && isObject(fromVal)) {
        mergeData(toVal, fromVal);
      }
    }
    return to;
  }

  /**
   * Data
   */

  strats.data = function (parentVal, childVal, vm) {
    if (!vm) {
      // in a Vue.extend merge, both should be functions
      if (!childVal) {
        return parentVal;
      }
      if (typeof childVal !== 'function') {
        'development' !== 'production' && warn('The "data" option should be a function ' + 'that returns a per-instance value in component ' + 'definitions.', vm);
        return parentVal;
      }
      if (!parentVal) {
        return childVal;
      }
      // when parentVal & childVal are both present,
      // we need to return a function that returns the
      // merged result of both functions... no need to
      // check if parentVal is a function here because
      // it has to be a function to pass previous merges.
      return function mergedDataFn() {
        return mergeData(childVal.call(this), parentVal.call(this));
      };
    } else if (parentVal || childVal) {
      return function mergedInstanceDataFn() {
        // instance merge
        var instanceData = typeof childVal === 'function' ? childVal.call(vm) : childVal;
        var defaultData = typeof parentVal === 'function' ? parentVal.call(vm) : undefined;
        if (instanceData) {
          return mergeData(instanceData, defaultData);
        } else {
          return defaultData;
        }
      };
    }
  };

  /**
   * El
   */

  strats.el = function (parentVal, childVal, vm) {
    if (!vm && childVal && typeof childVal !== 'function') {
      'development' !== 'production' && warn('The "el" option should be a function ' + 'that returns a per-instance value in component ' + 'definitions.', vm);
      return;
    }
    var ret = childVal || parentVal;
    // invoke the element factory if this is instance merge
    return vm && typeof ret === 'function' ? ret.call(vm) : ret;
  };

  /**
   * Hooks and param attributes are merged as arrays.
   */

  strats.init = strats.created = strats.ready = strats.attached = strats.detached = strats.beforeCompile = strats.compiled = strats.beforeDestroy = strats.destroyed = strats.activate = function (parentVal, childVal) {
    return childVal ? parentVal ? parentVal.concat(childVal) : isArray(childVal) ? childVal : [childVal] : parentVal;
  };

  /**
   * Assets
   *
   * When a vm is present (instance creation), we need to do
   * a three-way merge between constructor options, instance
   * options and parent options.
   */

  function mergeAssets(parentVal, childVal) {
    var res = Object.create(parentVal || null);
    return childVal ? extend(res, guardArrayAssets(childVal)) : res;
  }

  config._assetTypes.forEach(function (type) {
    strats[type + 's'] = mergeAssets;
  });

  /**
   * Events & Watchers.
   *
   * Events & watchers hashes should not overwrite one
   * another, so we merge them as arrays.
   */

  strats.watch = strats.events = function (parentVal, childVal) {
    if (!childVal) return parentVal;
    if (!parentVal) return childVal;
    var ret = {};
    extend(ret, parentVal);
    for (var key in childVal) {
      var parent = ret[key];
      var child = childVal[key];
      if (parent && !isArray(parent)) {
        parent = [parent];
      }
      ret[key] = parent ? parent.concat(child) : [child];
    }
    return ret;
  };

  /**
   * Other object hashes.
   */

  strats.props = strats.methods = strats.computed = function (parentVal, childVal) {
    if (!childVal) return parentVal;
    if (!parentVal) return childVal;
    var ret = Object.create(null);
    extend(ret, parentVal);
    extend(ret, childVal);
    return ret;
  };

  /**
   * Default strategy.
   */

  var defaultStrat = function defaultStrat(parentVal, childVal) {
    return childVal === undefined ? parentVal : childVal;
  };

  /**
   * Make sure component options get converted to actual
   * constructors.
   *
   * @param {Object} options
   */

  function guardComponents(options) {
    if (options.components) {
      var components = options.components = guardArrayAssets(options.components);
      var ids = Object.keys(components);
      var def;
      if ('development' !== 'production') {
        var map = options._componentNameMap = {};
      }
      for (var i = 0, l = ids.length; i < l; i++) {
        var key = ids[i];
        if (commonTagRE.test(key) || reservedTagRE.test(key)) {
          'development' !== 'production' && warn('Do not use built-in or reserved HTML elements as component ' + 'id: ' + key);
          continue;
        }
        // record a all lowercase <-> kebab-case mapping for
        // possible custom element case error warning
        if ('development' !== 'production') {
          map[key.replace(/-/g, '').toLowerCase()] = hyphenate(key);
        }
        def = components[key];
        if (isPlainObject(def)) {
          components[key] = Vue.extend(def);
        }
      }
    }
  }

  /**
   * Ensure all props option syntax are normalized into the
   * Object-based format.
   *
   * @param {Object} options
   */

  function guardProps(options) {
    var props = options.props;
    var i, val;
    if (isArray(props)) {
      options.props = {};
      i = props.length;
      while (i--) {
        val = props[i];
        if (typeof val === 'string') {
          options.props[val] = null;
        } else if (val.name) {
          options.props[val.name] = val;
        }
      }
    } else if (isPlainObject(props)) {
      var keys = Object.keys(props);
      i = keys.length;
      while (i--) {
        val = props[keys[i]];
        if (typeof val === 'function') {
          props[keys[i]] = { type: val };
        }
      }
    }
  }

  /**
   * Guard an Array-format assets option and converted it
   * into the key-value Object format.
   *
   * @param {Object|Array} assets
   * @return {Object}
   */

  function guardArrayAssets(assets) {
    if (isArray(assets)) {
      var res = {};
      var i = assets.length;
      var asset;
      while (i--) {
        asset = assets[i];
        var id = typeof asset === 'function' ? asset.options && asset.options.name || asset.id : asset.name || asset.id;
        if (!id) {
          'development' !== 'production' && warn('Array-syntax assets must provide a "name" or "id" field.');
        } else {
          res[id] = asset;
        }
      }
      return res;
    }
    return assets;
  }

  /**
   * Merge two option objects into a new one.
   * Core utility used in both instantiation and inheritance.
   *
   * @param {Object} parent
   * @param {Object} child
   * @param {Vue} [vm] - if vm is present, indicates this is
   *                     an instantiation merge.
   */

  function mergeOptions(parent, child, vm) {
    guardComponents(child);
    guardProps(child);
    if ('development' !== 'production') {
      if (child.propsData && !vm) {
        warn('propsData can only be used as an instantiation option.');
      }
    }
    var options = {};
    var key;
    if (child['extends']) {
      parent = typeof child['extends'] === 'function' ? mergeOptions(parent, child['extends'].options, vm) : mergeOptions(parent, child['extends'], vm);
    }
    if (child.mixins) {
      for (var i = 0, l = child.mixins.length; i < l; i++) {
        var mixin = child.mixins[i];
        var mixinOptions = mixin.prototype instanceof Vue ? mixin.options : mixin;
        parent = mergeOptions(parent, mixinOptions, vm);
      }
    }
    for (key in parent) {
      mergeField(key);
    }
    for (key in child) {
      if (!hasOwn(parent, key)) {
        mergeField(key);
      }
    }
    function mergeField(key) {
      var strat = strats[key] || defaultStrat;
      options[key] = strat(parent[key], child[key], vm, key);
    }
    return options;
  }

  /**
   * Resolve an asset.
   * This function is used because child instances need access
   * to assets defined in its ancestor chain.
   *
   * @param {Object} options
   * @param {String} type
   * @param {String} id
   * @param {Boolean} warnMissing
   * @return {Object|Function}
   */

  function resolveAsset(options, type, id, warnMissing) {
    /* istanbul ignore if */
    if (typeof id !== 'string') {
      return;
    }
    var assets = options[type];
    var camelizedId;
    var res = assets[id] ||
    // camelCase ID
    assets[camelizedId = camelize(id)] ||
    // Pascal Case ID
    assets[camelizedId.charAt(0).toUpperCase() + camelizedId.slice(1)];
    if ('development' !== 'production' && warnMissing && !res) {
      warn('Failed to resolve ' + type.slice(0, -1) + ': ' + id, options);
    }
    return res;
  }

  var util = Object.freeze({
  	defineReactive: defineReactive,
  	set: set,
  	del: del,
  	hasOwn: hasOwn,
  	isLiteral: isLiteral,
  	isReserved: isReserved,
  	_toString: _toString,
  	toNumber: toNumber,
  	toBoolean: toBoolean,
  	stripQuotes: stripQuotes,
  	camelize: camelize,
  	hyphenate: hyphenate,
  	classify: classify,
  	bind: bind,
  	toArray: toArray,
  	extend: extend,
  	isObject: isObject,
  	isPlainObject: isPlainObject,
  	def: def,
  	debounce: _debounce,
  	indexOf: indexOf,
  	cancellable: cancellable,
  	looseEqual: looseEqual,
  	isArray: isArray,
  	hasProto: hasProto,
  	inBrowser: inBrowser,
  	devtools: devtools,
  	isIE: isIE,
  	isIE9: isIE9,
  	isAndroid: isAndroid,
  	isIOS: isIOS,
  	get transitionProp () { return transitionProp; },
  	get transitionEndEvent () { return transitionEndEvent; },
  	get animationProp () { return animationProp; },
  	get animationEndEvent () { return animationEndEvent; },
  	nextTick: nextTick,
  	get _Set () { return Set$1; },
  	query: query,
  	inDoc: inDoc,
  	getAttr: getAttr,
  	getBindAttr: getBindAttr,
  	hasBindAttr: hasBindAttr,
  	before: before,
  	after: after,
  	remove: remove,
  	prepend: prepend,
  	replace: replace,
  	on: on,
  	off: off,
  	setClass: setClass,
  	addClass: addClass,
  	removeClass: removeClass,
  	extractContent: extractContent,
  	trimNode: trimNode,
  	isTemplate: isTemplate,
  	createAnchor: createAnchor,
  	findRef: findRef,
  	mapNodeRange: mapNodeRange,
  	removeNodeRange: removeNodeRange,
  	isFragment: isFragment,
  	getOuterHTML: getOuterHTML,
  	mergeOptions: mergeOptions,
  	resolveAsset: resolveAsset,
  	checkComponentAttr: checkComponentAttr,
  	commonTagRE: commonTagRE,
  	reservedTagRE: reservedTagRE,
  	get warn () { return warn; }
  });

  /**
   * Append with transition.
   *
   * @param {Element} el
   * @param {Element} target
   * @param {Vue} vm
   * @param {Function} [cb]
   */

  function appendWithTransition(el, target, vm, cb) {
    applyTransition(el, 1, function () {
      target.appendChild(el);
    }, vm, cb);
  }

  /**
   * InsertBefore with transition.
   *
   * @param {Element} el
   * @param {Element} target
   * @param {Vue} vm
   * @param {Function} [cb]
   */

  function beforeWithTransition(el, target, vm, cb) {
    applyTransition(el, 1, function () {
      before(el, target);
    }, vm, cb);
  }

  /**
   * Remove with transition.
   *
   * @param {Element} el
   * @param {Vue} vm
   * @param {Function} [cb]
   */

  function removeWithTransition(el, vm, cb) {
    applyTransition(el, -1, function () {
      remove(el);
    }, vm, cb);
  }

  /**
   * Apply transitions with an operation callback.
   *
   * @param {Element} el
   * @param {Number} direction
   *                  1: enter
   *                 -1: leave
   * @param {Function} op - the actual DOM operation
   * @param {Vue} vm
   * @param {Function} [cb]
   */

  function applyTransition(el, direction, op, vm, cb) {
    var transition = el.__v_trans;
    if (!transition ||
    // skip if there are no js hooks and CSS transition is
    // not supported
    !transition.hooks && !transitionEndEvent ||
    // skip transitions for initial compile
    !vm._isCompiled ||
    // if the vm is being manipulated by a parent directive
    // during the parent's compilation phase, skip the
    // animation.
    vm.$parent && !vm.$parent._isCompiled) {
      op();
      if (cb) cb();
      return;
    }
    var action = direction > 0 ? 'enter' : 'leave';
    transition[action](op, cb);
  }

  var transition = Object.freeze({
    appendWithTransition: appendWithTransition,
    beforeWithTransition: beforeWithTransition,
    removeWithTransition: removeWithTransition,
    applyTransition: applyTransition
  });

  var convertArray = vFor._postProcess;

  /**
   * Limit filter for arrays
   *
   * @param {Number} n
   * @param {Number} offset (Decimal expected)
   */

  function limitBy(arr, n, offset) {
    offset = offset ? parseInt(offset, 10) : 0;
    n = toNumber(n);
    return typeof n === 'number' ? arr.slice(offset, offset + n) : arr;
  }

  /**
   * Filter filter for arrays
   *
   * @param {String} search
   * @param {String} [delimiter]
   * @param {String} ...dataKeys
   */

  function filterBy(arr, search, delimiter) {
    arr = convertArray(arr);
    if (search == null) {
      return arr;
    }
    if (typeof search === 'function') {
      return arr.filter(search);
    }
    // cast to lowercase string
    search = ('' + search).toLowerCase();
    // allow optional `in` delimiter
    // because why not
    var n = delimiter === 'in' ? 3 : 2;
    // extract and flatten keys
    var keys = Array.prototype.concat.apply([], toArray(arguments, n));
    var res = [];
    var item, key, val, j;
    for (var i = 0, l = arr.length; i < l; i++) {
      item = arr[i];
      val = item && item.$value || item;
      j = keys.length;
      if (j) {
        while (j--) {
          key = keys[j];
          if (key === '$key' && contains(item.$key, search) || contains(getPath(val, key), search)) {
            res.push(item);
            break;
          }
        }
      } else if (contains(item, search)) {
        res.push(item);
      }
    }
    return res;
  }

  /**
   * Order filter for arrays
   *
   * @param {String|Array<String>|Function} ...sortKeys
   * @param {Number} [order]
   */

  function orderBy(arr) {
    var comparator = null;
    var sortKeys = undefined;
    arr = convertArray(arr);

    // determine order (last argument)
    var args = toArray(arguments, 1);
    var order = args[args.length - 1];
    if (typeof order === 'number') {
      order = order < 0 ? -1 : 1;
      args = args.length > 1 ? args.slice(0, -1) : args;
    } else {
      order = 1;
    }

    // determine sortKeys & comparator
    var firstArg = args[0];
    if (!firstArg) {
      return arr;
    } else if (typeof firstArg === 'function') {
      // custom comparator
      comparator = function (a, b) {
        return firstArg(a, b) * order;
      };
    } else {
      // string keys. flatten first
      sortKeys = Array.prototype.concat.apply([], args);
      comparator = function (a, b, i) {
        i = i || 0;
        return i >= sortKeys.length - 1 ? baseCompare(a, b, i) : baseCompare(a, b, i) || comparator(a, b, i + 1);
      };
    }

    function baseCompare(a, b, sortKeyIndex) {
      var sortKey = sortKeys[sortKeyIndex];
      if (sortKey) {
        if (sortKey !== '$key') {
          if (isObject(a) && '$value' in a) a = a.$value;
          if (isObject(b) && '$value' in b) b = b.$value;
        }
        a = isObject(a) ? getPath(a, sortKey) : a;
        b = isObject(b) ? getPath(b, sortKey) : b;
      }
      return a === b ? 0 : a > b ? order : -order;
    }

    // sort on a copy to avoid mutating original array
    return arr.slice().sort(comparator);
  }

  /**
   * String contain helper
   *
   * @param {*} val
   * @param {String} search
   */

  function contains(val, search) {
    var i;
    if (isPlainObject(val)) {
      var keys = Object.keys(val);
      i = keys.length;
      while (i--) {
        if (contains(val[keys[i]], search)) {
          return true;
        }
      }
    } else if (isArray(val)) {
      i = val.length;
      while (i--) {
        if (contains(val[i], search)) {
          return true;
        }
      }
    } else if (val != null) {
      return val.toString().toLowerCase().indexOf(search) > -1;
    }
  }

  var digitsRE = /(\d{3})(?=\d)/g;

  // asset collections must be a plain object.
  var filters = {

    orderBy: orderBy,
    filterBy: filterBy,
    limitBy: limitBy,

    /**
     * Stringify value.
     *
     * @param {Number} indent
     */

    json: {
      read: function read(value, indent) {
        return typeof value === 'string' ? value : JSON.stringify(value, null, arguments.length > 1 ? indent : 2);
      },
      write: function write(value) {
        try {
          return JSON.parse(value);
        } catch (e) {
          return value;
        }
      }
    },

    /**
     * 'abc' => 'Abc'
     */

    capitalize: function capitalize(value) {
      if (!value && value !== 0) return '';
      value = value.toString();
      return value.charAt(0).toUpperCase() + value.slice(1);
    },

    /**
     * 'abc' => 'ABC'
     */

    uppercase: function uppercase(value) {
      return value || value === 0 ? value.toString().toUpperCase() : '';
    },

    /**
     * 'AbC' => 'abc'
     */

    lowercase: function lowercase(value) {
      return value || value === 0 ? value.toString().toLowerCase() : '';
    },

    /**
     * 12345 => $12,345.00
     *
     * @param {String} sign
     * @param {Number} decimals Decimal places
     */

    currency: function currency(value, _currency, decimals) {
      value = parseFloat(value);
      if (!isFinite(value) || !value && value !== 0) return '';
      _currency = _currency != null ? _currency : '$';
      decimals = decimals != null ? decimals : 2;
      var stringified = Math.abs(value).toFixed(decimals);
      var _int = decimals ? stringified.slice(0, -1 - decimals) : stringified;
      var i = _int.length % 3;
      var head = i > 0 ? _int.slice(0, i) + (_int.length > 3 ? ',' : '') : '';
      var _float = decimals ? stringified.slice(-1 - decimals) : '';
      var sign = value < 0 ? '-' : '';
      return sign + _currency + head + _int.slice(i).replace(digitsRE, '$1,') + _float;
    },

    /**
     * 'item' => 'items'
     *
     * @params
     *  an array of strings corresponding to
     *  the single, double, triple ... forms of the word to
     *  be pluralized. When the number to be pluralized
     *  exceeds the length of the args, it will use the last
     *  entry in the array.
     *
     *  e.g. ['single', 'double', 'triple', 'multiple']
     */

    pluralize: function pluralize(value) {
      var args = toArray(arguments, 1);
      var length = args.length;
      if (length > 1) {
        var index = value % 10 - 1;
        return index in args ? args[index] : args[length - 1];
      } else {
        return args[0] + (value === 1 ? '' : 's');
      }
    },

    /**
     * Debounce a handler function.
     *
     * @param {Function} handler
     * @param {Number} delay = 300
     * @return {Function}
     */

    debounce: function debounce(handler, delay) {
      if (!handler) return;
      if (!delay) {
        delay = 300;
      }
      return _debounce(handler, delay);
    }
  };

  var partial = {

    priority: PARTIAL,

    params: ['name'],

    // watch changes to name for dynamic partials
    paramWatchers: {
      name: function name(value) {
        vIf.remove.call(this);
        if (value) {
          this.insert(value);
        }
      }
    },

    bind: function bind() {
      this.anchor = createAnchor('v-partial');
      replace(this.el, this.anchor);
      this.insert(this.params.name);
    },

    insert: function insert(id) {
      var partial = resolveAsset(this.vm.$options, 'partials', id, true);
      if (partial) {
        this.factory = new FragmentFactory(this.vm, partial);
        vIf.insert.call(this);
      }
    },

    unbind: function unbind() {
      if (this.frag) {
        this.frag.destroy();
      }
    }
  };

  var slot = {

    priority: SLOT,
    params: ['name'],

    bind: function bind() {
      // this was resolved during component transclusion
      var name = this.params.name || 'default';
      var content = this.vm._slotContents && this.vm._slotContents[name];
      if (!content || !content.hasChildNodes()) {
        this.fallback();
      } else {
        this.compile(content.cloneNode(true), this.vm._context, this.vm);
      }
    },

    compile: function compile(content, context, host) {
      if (content && context) {
        if (this.el.hasChildNodes() && content.childNodes.length === 1 && content.childNodes[0].nodeType === 1 && content.childNodes[0].hasAttribute('v-if')) {
          // if the inserted slot has v-if
          // inject fallback content as the v-else
          var elseBlock = document.createElement('template');
          elseBlock.setAttribute('v-else', '');
          elseBlock.innerHTML = this.el.innerHTML;
          // the else block should be compiled in child scope
          elseBlock._context = this.vm;
          content.appendChild(elseBlock);
        }
        var scope = host ? host._scope : this._scope;
        this.unlink = context.$compile(content, host, scope, this._frag);
      }
      if (content) {
        replace(this.el, content);
      } else {
        remove(this.el);
      }
    },

    fallback: function fallback() {
      this.compile(extractContent(this.el, true), this.vm);
    },

    unbind: function unbind() {
      if (this.unlink) {
        this.unlink();
      }
    }
  };

  var elementDirectives = {
    slot: slot,
    partial: partial
  };

  function installGlobalAPI (Vue) {
    /**
     * Vue and every constructor that extends Vue has an
     * associated options object, which can be accessed during
     * compilation steps as `this.constructor.options`.
     *
     * These can be seen as the default options of every
     * Vue instance.
     */

    Vue.options = {
      directives: publicDirectives,
      elementDirectives: elementDirectives,
      filters: filters,
      transitions: {},
      components: {},
      partials: {},
      replace: true
    };

    /**
     * Expose useful internals
     */

    Vue.util = util;
    Vue.config = config;
    Vue.set = set;
    Vue['delete'] = del;
    Vue.nextTick = nextTick;

    /**
     * The following are exposed for advanced usage / plugins
     */

    Vue.compiler = compiler;
    Vue.FragmentFactory = FragmentFactory;
    Vue.internalDirectives = internalDirectives;
    Vue.parsers = {
      path: path,
      text: text,
      template: template,
      directive: directive,
      expression: expression
    };

    /**
     * Each instance constructor, including Vue, has a unique
     * cid. This enables us to create wrapped "child
     * constructors" for prototypal inheritance and cache them.
     */

    Vue.cid = 0;
    var cid = 1;

    /**
     * Class inheritance
     *
     * @param {Object} extendOptions
     */

    Vue.extend = function (extendOptions) {
      extendOptions = extendOptions || {};
      var Super = this;
      var isFirstExtend = Super.cid === 0;
      if (isFirstExtend && extendOptions._Ctor) {
        return extendOptions._Ctor;
      }
      var name = extendOptions.name || Super.options.name;
      if ('development' !== 'production') {
        if (!/^[a-zA-Z][\w-]*$/.test(name)) {
          warn('Invalid component name: "' + name + '". Component names ' + 'can only contain alphanumeric characaters and the hyphen.');
          name = null;
        }
      }
      var Sub = createClass(name || 'VueComponent');
      Sub.prototype = Object.create(Super.prototype);
      Sub.prototype.constructor = Sub;
      Sub.cid = cid++;
      Sub.options = mergeOptions(Super.options, extendOptions);
      Sub['super'] = Super;
      // allow further extension
      Sub.extend = Super.extend;
      // create asset registers, so extended classes
      // can have their private assets too.
      config._assetTypes.forEach(function (type) {
        Sub[type] = Super[type];
      });
      // enable recursive self-lookup
      if (name) {
        Sub.options.components[name] = Sub;
      }
      // cache constructor
      if (isFirstExtend) {
        extendOptions._Ctor = Sub;
      }
      return Sub;
    };

    /**
     * A function that returns a sub-class constructor with the
     * given name. This gives us much nicer output when
     * logging instances in the console.
     *
     * @param {String} name
     * @return {Function}
     */

    function createClass(name) {
      /* eslint-disable no-new-func */
      return new Function('return function ' + classify(name) + ' (options) { this._init(options) }')();
      /* eslint-enable no-new-func */
    }

    /**
     * Plugin system
     *
     * @param {Object} plugin
     */

    Vue.use = function (plugin) {
      /* istanbul ignore if */
      if (plugin.installed) {
        return;
      }
      // additional parameters
      var args = toArray(arguments, 1);
      args.unshift(this);
      if (typeof plugin.install === 'function') {
        plugin.install.apply(plugin, args);
      } else {
        plugin.apply(null, args);
      }
      plugin.installed = true;
      return this;
    };

    /**
     * Apply a global mixin by merging it into the default
     * options.
     */

    Vue.mixin = function (mixin) {
      Vue.options = mergeOptions(Vue.options, mixin);
    };

    /**
     * Create asset registration methods with the following
     * signature:
     *
     * @param {String} id
     * @param {*} definition
     */

    config._assetTypes.forEach(function (type) {
      Vue[type] = function (id, definition) {
        if (!definition) {
          return this.options[type + 's'][id];
        } else {
          /* istanbul ignore if */
          if ('development' !== 'production') {
            if (type === 'component' && (commonTagRE.test(id) || reservedTagRE.test(id))) {
              warn('Do not use built-in or reserved HTML elements as component ' + 'id: ' + id);
            }
          }
          if (type === 'component' && isPlainObject(definition)) {
            if (!definition.name) {
              definition.name = id;
            }
            definition = Vue.extend(definition);
          }
          this.options[type + 's'][id] = definition;
          return definition;
        }
      };
    });

    // expose internal transition API
    extend(Vue.transition, transition);
  }

  installGlobalAPI(Vue);

  Vue.version = '1.0.28';

  // devtools global hook
  /* istanbul ignore next */
  setTimeout(function () {
    if (config.devtools) {
      if (devtools) {
        devtools.emit('init', Vue);
      } else if ('development' !== 'production' && inBrowser && /Chrome\/\d+/.test(window.navigator.userAgent)) {
        console.log('Download the Vue Devtools for a better development experience:\n' + 'https://github.com/vuejs/vue-devtools');
      }
    }
  }, 0);

  return Vue;

}));