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Iterable WeakSet in JavaScript
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| // spec: https://github.com/tc39/proposal-weakrefs | |
| // the spec contains an [iterable WeakMap implementation](https://github.com/tc39/proposal-weakrefs#iterable-weakmaps) | |
| // NOTE: this WeakSet implementation is incomplete, only does what I needed | |
| // In Firefox Nightly, visit about:config and enable javascript.options.experimental.weakrefs | |
| class IterableWeakSet extends Set { | |
| add(el) { | |
| super.add(new WeakRef(el)) | |
| } | |
| forEach(fn) { | |
| super.forEach(ref => { | |
| const value = ref.deref() | |
| if (value) fn(value) | |
| }) | |
| } | |
| *[Symbol.iterator]() { | |
| for (const ref of super.values()) { | |
| const value = ref.deref() | |
| if (value) yield value | |
| } | |
| } | |
| } |
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