All files / lib/internal/util iterable_weak_map.js

100% Statements 84/84
100% Branches 18/18
100% Functions 7/7
100% Lines 84/84

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85140x 140x 140x 140x 140x 140x 140x 140x 140x 140x 140x 140x 140x 140x 140x 146x 146x 146x 146x 146x 146x 223x 223x 1x 1x 1x 223x 222x 222x 222x 222x 222x 222x 222x 222x 223x 146x 146x 1x 1x 146x 146x 1x 1x 146x 146x 2x 2x 1x 1x 1x 1x 1x 1x 2x 146x 146x 65x 65x 65x 129x 129x 64x 129x 63x 63x 65x 65x 65x 65x 65x 65x 65x 146x 140x 1x 1x 1x 140x 140x 140x 140x 140x 140x  
'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,
};