WeakMap
Widely available since 2018-01-29
A WeakMap object holds key-value pairs that do not create strong references to its keys, such that value data can be associated with a key without preventing garbage collection of the key.
Learning resources on MDN
Browser support
- Chrome 36 Released on 2014-07-16
- Chrome Android 36 Released on 2014-07-16
- Edge 12 Released on 2015-07-29
- Firefox 6 Released on 2011-08-16
- Firefox for Android 6 Released on 2011-08-16
- Safari 8 Released on 2014-10-16
- Safari on iOS 8 Released on 2014-09-17
Specifications
- ECMAScript Language Specification (#sec-weakmap-objects), from TC39 (Ecma International).