weakmap-polyfill

What is weakmap-polyfill?

The weakmap-polyfill npm package provides a polyfill for the WeakMap object, which is a collection of key/value pairs where the keys are objects and the values can be arbitrary values. This polyfill is useful for environments that do not natively support WeakMap.

What are weakmap-polyfill's main functionalities?

Creating a WeakMap

This feature allows you to create a new instance of a WeakMap using the polyfill.

const WeakMapPolyfill = require('weakmap-polyfill');
const wm = new WeakMapPolyfill();

Setting a value

This feature allows you to set a value in the WeakMap for a specific object key.

const obj = {};
wm.set(obj, 'value');

Getting a value

This feature allows you to retrieve a value from the WeakMap using an object key.

const value = wm.get(obj);

Checking for a key

This feature allows you to check if a specific object key exists in the WeakMap.

const hasKey = wm.has(obj);

Deleting a key

This feature allows you to remove a key/value pair from the WeakMap.

wm.delete(obj);

Other packages similar to weakmap-polyfill

core-js

core-js is a modular standard library for JavaScript that includes polyfills for various ECMAScript features, including WeakMap. It provides a comprehensive set of polyfills for modern JavaScript features, making it a more extensive solution compared to weakmap-polyfill.

es6-weak-map

es6-weak-map is another polyfill for the WeakMap object. It provides similar functionality to weakmap-polyfill but is specifically focused on WeakMap, making it a more lightweight alternative to core-js.

README

weakmap-polyfill

ECMAScript6 WeakMap polyfill.

Installation

npm

$ npm install --save weakmap-polyfill

Usage

Import or require weakmap-polyfill, then WeakMap will be defined in the global scope if native WeakMap is not supported in running environment.

using import

import 'weakmap-polyfill';
const weakMap = new WeakMap();

using require

require('weakmap-polyfill');
var weakMap = new WeakMap();

browser (standalone)

<script src="weakmap-polyfill.min.js"></script>
<script>
var weakMap = new WeakMap();
</script>

Compatibility

• Chrome 15
• Firefox 3
• IE 7
• Safari 4
• Opera 11.5
• Edge

Browser Tests

• Browser Test
• Browser Test for Legacy

Limitations

This polyfill has following few limitations.

• WeakMap iterable argument is not supported. (23.3.1.1 WeakMap ( [ iterable ] ))
• Frozen and sealed objects are not supported.
• The values held by a WeakMap can't be collected once the map itself is GCed, since the values here are tied to the keys. #4

License

MIT