index.js

'use strict';

/**
 * Module dependencies
 */
var decouple = require('decouple');

/**
 * Privates
 */
var scrollTimeout;
var scrolling = false;
var doc = window.document;
var html = doc.documentElement;
var msPointerSupported = window.navigator.msPointerEnabled;
var touch = {
  'start': msPointerSupported ? 'MSPointerDown' : 'touchstart',
  'move': msPointerSupported ? 'MSPointerMove' : 'touchmove',
  'end': msPointerSupported ? 'MSPointerUp' : 'touchend'
};
var prefix = (function prefix() {
  var regex = /^(Webkit|Khtml|Moz|ms|O)(?=[A-Z])/;
  var styleDeclaration = doc.getElementsByTagName('script')[0].style;
  for (var prop in styleDeclaration) {
    if (regex.test(prop)) {
      return '-' + prop.match(regex)[0].toLowerCase() + '-';
    }
  }
  // Nothing found so far? Webkit does not enumerate over the CSS properties of the style object.
  // However (prop in style) returns the correct value, so we'll have to test for
  // the precence of a specific property
  if ('WebkitOpacity' in styleDeclaration) { return '-webkit-'; }
  if ('KhtmlOpacity' in styleDeclaration) { return '-khtml-'; }
  return '';
}());

/**
 * Slideout constructor
 */
function Slideout(options) {
  options = options || {};

  // Sets default values
  this._startOffsetX = 0;
  this._currentOffsetX = 0;
  this._opening = false;
  this._moved = false;
  this._opened = false;
  this._preventOpen = false;

  // Sets panel
  this.panel = options.panel;
  this.menu = options.menu;

  // Sets  classnames
  this.panel.className += ' slideout-panel';
  this.menu.className += ' slideout-menu';

  // Sets options
  this._fx = options.fx || 'ease';
  this._duration = parseInt(options.duration, 10) || 300;
  this._tolerance = parseInt(options.tolerance, 10) || 70;
  this._padding = parseInt(options.padding, 10) || 256;

  // Init touch events
  this._initTouchEvents();
}

/**
 * Opens the slideout menu.
 */
Slideout.prototype.open = function() {
  var self = this;
  if (html.className.search('slideout-open') === -1) { html.className += ' slideout-open'; }
  this._setTransition();
  this._translateXTo(this._padding);
  this._opened = true;
  setTimeout(function() {
    self.panel.style.transition = self.panel.style['-webkit-transition'] = '';
  }, this._duration + 50);
  return this;
};

/**
 * Closes slideout menu.
 */
Slideout.prototype.close = function() {
  var self = this;
  if (!this.isOpen() && !this._opening) { return this; }
  this._setTransition();
  this._translateXTo(0);
  this._opened = false;
  setTimeout(function() {
    html.className = html.className.replace(/ slideout-open/, '');
    self.panel.style.transition = self.panel.style['-webkit-transition'] = '';
  }, this._duration + 50);
  return this;
};

/**
 * Toggles (open/close) slideout menu.
 */
Slideout.prototype.toggle = function() {
  return this.isOpen() ? this.close() : this.open();
};

/**
 * Returns true if the slideout is currently open, and false if it is closed.
 */
Slideout.prototype.isOpen = function() {
  return this._opened;
};

/**
 * Translates panel and updates currentOffset with a given X point
 */
Slideout.prototype._translateXTo = function(translateX) {
  this._currentOffsetX = translateX;
  this.panel.style[prefix + 'transform'] = this.panel.style.transform = 'translate3d(' + translateX + 'px, 0, 0)';
};

/**
 * Set transition properties
 */
Slideout.prototype._setTransition = function() {
  this.panel.style[prefix + 'transition'] = this.panel.style.transition = prefix + 'transform ' + this._duration + 'ms ' + this._fx;
};

/**
 * Initializes touch event
 */
Slideout.prototype._initTouchEvents = function() {
  var self = this;

  /**
   * Decouple scroll event
   */
  decouple(doc, 'scroll', function() {
    if (!self._moved) {
      clearTimeout(scrollTimeout);
      scrolling = true;
      scrollTimeout = setTimeout(function() {
        scrolling = false;
      }, 250);
    }
  });

  /**
   * Prevents touchmove event if slideout is moving
   */
  doc.addEventListener(touch.move, function(eve) {
    if (self._moved) {
      eve.preventDefault();
    }
  });

  /**
   * Resets values on touchstart
   */
  this.panel.addEventListener(touch.start, function(eve) {
    self._moved = false;
    self._opening = false;
    self._startOffsetX = eve.touches[0].pageX;
    self._preventOpen = (!self.isOpen() && self.menu.clientWidth !== 0);
  });

  /**
   * Resets values on touchcancel
   */
  this.panel.addEventListener('touchcancel', function() {
    self._moved = false;
    self._opening = false;
  });

  /**
   * Toggles slideout on touchend
   */
  this.panel.addEventListener(touch.end, function() {
    if (self._moved) {
      (self._opening && Math.abs(self._currentOffsetX) > self._tolerance) ? self.open() : self.close();
    }
    self._moved = false;
  });

  /**
   * Translates panel on touchmove
   */
  this.panel.addEventListener(touch.move, function(eve) {

    if (scrolling || self._preventOpen) { return; }

    var dif_x = eve.touches[0].clientX - self._startOffsetX;
    var translateX = self._currentOffsetX = dif_x;

    if (Math.abs(translateX) > self._padding) { return; }

    if (Math.abs(dif_x) > 20) {
      self._opening = true;

      if (self._opened && dif_x > 0 || !self._opened && dif_x < 0) { return; }

      if (!self._moved && html.className.search('slideout-open') === -1) {
        html.className += ' slideout-open';
      }

      if (dif_x <= 0) {
        translateX = dif_x + self._padding;
        self._opening = false;
      }

      self.panel.style[prefix + 'transform'] = self.panel.style.transform = 'translate3d(' + translateX + 'px, 0, 0)';

      self._moved = true;
    }

  });

};

/**
 * Expose Slideout
 */
module.exports = Slideout;