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[Bugfix Beta] Improve Ember.Map
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* [Perf + ES6] no longer clone array before enumeration (dramatically reduce allocations)
* [Perf] Don’t rebind the callback of forEach if not needed
* [Perf + ES6] no longer allow Map#length to be bindable
* [Perf] don’t double guid keys, as they are passed from map to ordered set (add/remove)
* [ES6] deprecate Map#remove in-favor of the es6 Map#delete
* [ES6] error if callback is not a function
* [ES6] Map#set should return the map. This enables chaining map.`map.set(‘foo’,1).set(‘bar’,3);` etc
* [ES6] remove length in-favor of size.
* [ES6] throw if constructor is invoked without new
* [ES6] Make inheritance work correctly
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@stefanpenner
stefanpenner committed Sep 20, 2014
1 parent 5ddaa3e commit ccc53a3
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Showing 2 changed files with 321 additions and 61 deletions.
178 changes: 131 additions & 47 deletions packages/ember-metal/lib/map.js
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Original file line number Diff line number Diff line change
Expand Up @@ -22,13 +22,20 @@
`Ember.Map.create()` for symmetry with other Ember classes.
*/

import { set } from "ember-metal/property_set";
import { guidFor } from "ember-metal/utils";
import { indexOf } from "ember-metal/array";
import { create } from "ember-metal/platform";

function copy(obj) {
var output = {};
function missingFunction(fn) {
throw new TypeError('' + Object.prototype.toString.call(fn) + " is not a function");
}

function missingNew(name) {
throw new TypeError("Constructor " + name + "requires 'new'");
}

function copyNull(obj) {
var output = Object.create(null);

for (var prop in obj) {
// hasOwnPropery is not needed because obj is Object.create(null);
Expand All @@ -40,11 +47,11 @@ function copy(obj) {

function copyMap(original, newObject) {
var keys = original.keys.copy();
var values = copy(original.values);
var values = copyNull(original.values);

newObject.keys = keys;
newObject.values = values;
newObject.length = original.length;
newObject.size = original.size;

return newObject;
}
Expand All @@ -60,7 +67,12 @@ function copyMap(original, newObject) {
@private
*/
function OrderedSet() {
this.clear();

if (this instanceof OrderedSet) {
this.clear();
} else {
missingNew("OrderedSet");
}
}

/**
Expand All @@ -69,47 +81,77 @@ function OrderedSet() {
@return {Ember.OrderedSet}
*/
OrderedSet.create = function() {
return new OrderedSet();
var Constructor = this;

return new Constructor();
};

OrderedSet.prototype = {
constructor: OrderedSet,
/**
@method clear
*/
clear: function() {
this.presenceSet = Object.create(null);
this.list = [];
this.size = 0;
},

/**
@method add
@param obj
@param guid (optional, and for internal use)
@return {Ember.OrderedSet}
*/
add: function(obj) {
var guid = guidFor(obj);
add: function(obj, _guid) {
var guid = _guid || guidFor(obj);
var presenceSet = this.presenceSet;
var list = this.list;

if (presenceSet[guid]) { return; }
if (presenceSet[guid]) {
return;
}

presenceSet[guid] = true;
list.push(obj);
this.size++;

return this;
},

/**
@deprecated
@method remove
@param obj
@param _guid (optional and for internal use only)
@return {Boolean}
*/
remove: function(obj) {
var guid = guidFor(obj);
remove: function(obj, _guid) {
return this['delete'](obj, _guid);
},

/**
@method delete
@param obj
@param _guid (optional and for internal use only)
@return {Boolean}
*/
'delete': function(obj, _guid) {
var guid = _guid || guidFor(obj);
var presenceSet = this.presenceSet;
var list = this.list;

delete presenceSet[guid];

var index = indexOf.call(list, obj);
if (index > -1) {
list.splice(index, 1);
if (presenceSet[guid] !== undefined) {
delete presenceSet[guid];
var index = indexOf.call(list, obj);
if (index > -1) {
list.splice(index, 1);
}
this.size--;
return true;
} else {
return false;
}
},

Expand All @@ -118,7 +160,7 @@ OrderedSet.prototype = {
@return {Boolean}
*/
isEmpty: function() {
return this.list.length === 0;
return this.size === 0;
},

/**
Expand All @@ -130,20 +172,27 @@ OrderedSet.prototype = {
var guid = guidFor(obj);
var presenceSet = this.presenceSet;

return presenceSet[guid];
return !!presenceSet[guid];
},

/**
@method forEach
@param {Function} fn
@param self
*/
forEach: function(fn, self) {
// allow mutation during iteration
var list = this.toArray();
forEach: function(fn, thisArg) {
var list = this.list;
var length = arguments.length;
var i;

for (var i = 0, j = list.length; i < j; i++) {
fn.call(self, list[i]);
if (length === 2) {
for (i = 0; i < list.length; i++) {
fn.call(thisArg, list[i]);
}
} else {
for (i = 0; i < list.length; i++) {
fn(list[i]);
}
}
},

Expand All @@ -160,9 +209,10 @@ OrderedSet.prototype = {
@return {Ember.OrderedSet}
*/
copy: function() {
var set = new OrderedSet();
var Constructor = this.constructor;
var set = new Constructor();

set.presenceSet = copy(this.presenceSet);
set.presenceSet = copyNull(this.presenceSet);
set.list = this.toArray();

return set;
Expand Down Expand Up @@ -190,8 +240,13 @@ OrderedSet.prototype = {
@constructor
*/
function Map() {
this.keys = OrderedSet.create();
this.values = Object.create(null);
if (this instanceof this.constructor) {
this.keys = OrderedSet.create();
this.values = Object.create(null);
this.size = 0;
} else {
missingNew("OrderedSet");
}
}

Ember.Map = Map;
Expand All @@ -201,18 +256,21 @@ Ember.Map = Map;
@static
*/
Map.create = function() {
return new Map();
var Constructor = this;
return new Constructor();
};

Map.prototype = {
constructor: Map,

/**
This property will change as the number of objects in the map changes.
@property length
@property size
@type number
@default 0
*/
length: 0,
size: 0,

/**
Retrieve the value associated with a given key.
Expand All @@ -235,35 +293,51 @@ Map.prototype = {
@method set
@param {*} key
@param {*} value
@return {Ember.Map}
*/
set: function(key, value) {
var keys = this.keys;
var values = this.values;
var guid = guidFor(key);

keys.add(key);
keys.add(key, guid);
values[guid] = value;
set(this, 'length', keys.list.length);

this.size = keys.size;

return this;
},

/**
@deprecated see delete
Removes a value from the map for an associated key.
@method remove
@param {*} key
@return {Boolean} true if an item was removed, false otherwise
*/
remove: function(key) {
return this['delete'](key);
},

/**
Removes a value from the map for an associated key.
@method delete
@param {*} key
@return {Boolean} true if an item was removed, false otherwise
*/
'delete': function(key) {
// don't use ES6 "delete" because it will be annoying
// to use in browsers that are not ES6 friendly;
var keys = this.keys;
var values = this.values;
var guid = guidFor(key);

if (values[guid]) {
keys.remove(key);
keys.remove(key, guid);
delete values[guid];
set(this, 'length', keys.list.length);
this.size = keys.size;
return true;
} else {
return false;
Expand All @@ -278,10 +352,7 @@ Map.prototype = {
@return {Boolean} true if the item was present, false otherwise
*/
has: function(key) {
var values = this.values;
var guid = guidFor(key);

return !!values[guid];
return this.keys.has(key);
},

/**
Expand All @@ -295,14 +366,26 @@ Map.prototype = {
@param {*} self if passed, the `this` value inside the
callback. By default, `this` is the map.
*/
forEach: function(callback, self) {
var keys = this.keys;
var values = this.values;
forEach: function(callback, thisArg) {
if (typeof callback !== 'function') {
missingFunction(callback);
}

var length = arguments.length;
var map = this;
var cb;

if (length === 2) {
cb = function(key) {
callback.call(thisArg, map.get(key), key);
};
} else {
cb = function(key) {
callback(map.get(key), key);
};
}

keys.forEach(function(key) {
var guid = guidFor(key);
callback.call(self, key, values[guid]);
});
this.keys.forEach(cb);
},

/**
Expand Down Expand Up @@ -373,7 +456,8 @@ MapWithDefault.prototype.get = function(key) {
@return {Ember.MapWithDefault}
*/
MapWithDefault.prototype.copy = function() {
return copyMap(this, new MapWithDefault({
var Constructor = this.constructor;
return copyMap(this, new Constructor({
defaultValue: this.defaultValue
}));
};
Expand Down

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