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'use strict';
const {
ObjectFreeze,
SafeFinalizationRegistry,
SafeSet,
SafeWeakMap,
SafeWeakRef,
SymbolIterator,
} = primordials;
// This class is modified from the example code in the WeakRefs specification:
// https://github.com/tc39/proposal-weakrefs
// Licensed under ECMA's MIT-style license, see:
// https://github.com/tc39/ecma262/blob/HEAD/LICENSE.md
class IterableWeakMap {
#weakMap = new SafeWeakMap();
#refSet = new SafeSet();
#finalizationGroup = new SafeFinalizationRegistry(cleanup);
set(key, value) {
const entry = this.#weakMap.get(key);
if (entry) {
// If there's already an entry for the object represented by "key",
// the value can be updated without creating a new WeakRef:
this.#weakMap.set(key, { value, ref: entry.ref });
} else {
const ref = new SafeWeakRef(key);
this.#weakMap.set(key, { value, ref });
this.#refSet.add(ref);
this.#finalizationGroup.register(key, {
set: this.#refSet,
ref,
}, ref);
}
}
get(key) {
return this.#weakMap.get(key)?.value;
}
has(key) {
return this.#weakMap.has(key);
}
delete(key) {
const entry = this.#weakMap.get(key);
if (!entry) {
return false;
}
this.#weakMap.delete(key);
this.#refSet.delete(entry.ref);
this.#finalizationGroup.unregister(entry.ref);
return true;
}
[SymbolIterator]() {
const iterator = this.#refSet[SymbolIterator]();
const next = () => {
const result = iterator.next();
if (result.done) return result;
const key = result.value.deref();
if (key == null) return next();
const { value } = this.#weakMap.get(key);
return { done: false, value };
};
return {
[SymbolIterator]() { return this; },
next,
};
}
}
function cleanup({ set, ref }) {
set.delete(ref);
}
ObjectFreeze(IterableWeakMap.prototype);
module.exports = {
IterableWeakMap,
};
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