/
index.js
136 lines (113 loc) · 3.78 KB
/
index.js
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(function() {
// Standard module setup
// ---------------------
// Establish the root object, 'window' ('self') in the browser, 'global'
// on the server, or 'this' in some virtual machines. We use 'self'
// instead of 'window' for 'WebWorker' support.
var root = typeof self === 'object' && self.self === self && self ||
typeof global === 'object' && global.global === global && global ||
this;
// set execution environment
var env = typeof global === 'object' ? 'global' : 'window';
// Save previous value of memoize
if (root !== null) {
var previous_memoize = root.memoize;
}
// Safe reference to the memoize object
// Needed if we want to chain in OO eventually .. ?
var memoize = function(obj) {
if (obj instanceof memoize) return obj;
if (!(this instanceof memoize)) return new memoize(obj);
};
// Measure function performance
var functionPerformance = function(t) {
if (env !== 'global') {
return !t ? performance.now() : performance.now() - t;
} else {
return !t ? process.hrtime() : process.hrtime(t);
}
}
// Module functions
// ----------------
// Note: Functions do not follow DRY standards yet.
// Need to refactor
// Removes result of least frequently applied arguments from storage after cache limit reached
memoize.frequency = function(func, limit) {
var storage = Object.create(null),
frequency = Object.create(null),
limit = limit || Infinity,
resetLimit = limit,
least = undefined;
var memorized = function() {
var args = Array.prototype.slice.apply(arguments);
if (args in storage) {
frequency[args] = frequency[args] + 1
return storage[args];
}
if (!(args in storage) && limit < 1) {
least = Object.keys(frequency).reduce(function(least, key) {
return (least === undefined || frequency[key] < frequency[least]) ? key : least;
})
delete frequency[least] && delete storage[least];
} else limit--;
frequency[args] = frequency[args] + 1 || 1;
return (storage[args] = func.apply(this, args));
}
memorized._clear = function() {
storage = Object.create(null);
frequency = Object.create(null);
limit = resetLimit;
least = undefined;
return true
}
return memorized
}
// Removes result of best performing arguments from storage after cache limit is reached
memoize.performance = function(func, limit) {
var storage = Object.create(null),
performance = Object.create(null),
limit = limit || Infinity,
resetLimit = limit,
least = undefined;
var memorized = function() {
var args = Array.prototype.slice.apply(arguments);
if (args in storage) {
return storage[args];
}
if (limit < 1) {
var fastest = Object.keys(performance).reduce(function(fastest, key) {
return (fastest === undefined || performance[key] < performance[fastest]) ? key : fastest;
});
delete performance[fastest] && delete storage[fastest];
} else limit--;
var t = functionPerformance();
storage[args] = func.apply(this, args);
performance[args] = functionPerformance(t);
return storage[args];
}
memorized._clear = function() {
storage = Object.create(null);
performance = Object.create(null);
limit = resetLimit;
least = undefined;
return true
}
return memorized;
}
// Export
// -------
// For Node.js
if (typeof module === 'object' && module.exports) {
module.exports = memoize;
}
// AMD / RequireJS (needs to be at end of file)
else if (typeof define === 'function' && define.amd) {
define([], function() {
return memoize;
});
}
// For browser
else {
root.memoize = memoize;
}
}());