WeakSet

   !WebReflection status

An essential WeakSet poorlyfill legacy browsers that don't have even a WeakMap but need just a WeakSet.

* CDN via https://unpkg.com/@ungap/essential-weakset
* ESM via import WeakSet from '@ungap/essential-weakset'
* CJS via const WeakSet = require('@ungap/essential-weakset')

Compatible down to IE9, works well with ES5 shim upfront in IE8 (and maybe lower too).

Live test