API_REFERENCE.md

API Reference

Table of contents

• WeakMap
  • Constructor
    • from(mapEntries[, mapFn])
    • isWeakMap(x)
    • of(element0[, element1[, ...[, elementN]]])
  • Prototype

WeakMap

Constructor

from(mapEntries[, mapFn])

Creates a WeakMap object that contains all key/ value pairs of mapEntries with each key must be an object and an optional mapFn to call on every element of the mapEntries.

const key1 = {};
const key2 = {};
const entries = [
  [key1, 1],
  [key2, 2],
];
const m = Map.from(entries, (n) => {
  const k = n[0];
  const v = n[1];

  return [k, 1 + v];
});

m.get(key1) === 2;
m.get(key2) === 3;

isWeakMap(x)

Returns true if x is a WeakMap object.

WeakMap.isWeakMap(new WeakMap()) === true;

of(element0[, element1[, ...[, elementN]]])

Creates a new WeakMap object from a variable number of arguments, regardless of the number of type of the arguments.

const key1 = {};
const key2 = {};
const m = WeakMap.of([key1, 1], [key2, 2]);

m.get(key1) === 1;
m.get(key2) === 2;

Prototype

None