Ember WeakMap

This addon is a polyfill for the Ember.WeakMap RFC.

A WeakMap provides a mechanism for storing and retrieving private state. The WeakMap
itself does not retain a reference to the state, allowing the state to be reclaimed
when the key is reclaimed.

A traditional WeakMap (and the one that will be part of the ES2015 language) allows for
weakness from key -> map, and also from map -> key. This allows either the Map,
or the key being reclaimed to also release the state.

Unfortunately, this bi-directional weakness is problematic to polyfill.
Luckily, uni-directional weakness, in either direction, "just works". A polyfill
must just choose a direction.

Note: Just like ES2015 WeakMap, only non null Objects can be used as keys

Installation

``shell
ember install ember-weakmap
`

Usage

`js
import Ember from 'ember';

const myWeakMap = new Ember.WeakMap();
`

$3

`js
/*
* @method set
* @param key {Object}
* @param value {Any}
* @return {Any} stored value
*/

const emailObj = { id: 1, subject: 'Hello World' };

myWeakMap.set(emailObj, {read: true});
`

The key must be an object.

$3

`js
/*
* @method get
* @param key {Object}
@return {} stored value
*/

myWeakMap.get(emailObj); // => { read: true }
myWeakMap.get(someObjThatWasNotSet); // => undefined
`

$3

`js
/*
* @method has
* @param key {Object}
* @return {Boolean} if the key exists
*/

myWeakMap.has(emailObj); // => true
myWeakMap.has(someObjThatWasNotSet); // => false
`

$3

`js
/*
* @method delete
* @param key {Object}
*/

myWeakMap.delete(emailObj);
myWeakMap.get(emailObj); // => undefined
myWeakMap.has(emailObj); // false
``