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

ember install ember-weakmap

Usage

importEmberfrom'ember';constmyWeakMap=newEmber.WeakMap();

Set

/* * @method set * @param key {Object} * @param value {Any} * @return {Any} stored value */constemailObj={id: 1,subject: 'Hello World'};myWeakMap.set(emailObj,{read: true});

The key must be an object.

Get

/* * @method get * @param key {Object} * @return {*} stored value*/myWeakMap.get(emailObj);// => { read: true }myWeakMap.get(someObjThatWasNotSet);// => undefined

Has

/* * @method has * @param key {Object} * @return {Boolean} if the key exists*/myWeakMap.has(emailObj);// => truemyWeakMap.has(someObjThatWasNotSet);// => false

Delete

/* * @method delete * @param key {Object} */myWeakMap.delete(emailObj);myWeakMap.get(emailObj);// => undefinedmyWeakMap.has(emailObj);// false