WeakMap.prototype.set()

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Theset() method ofWeakMap instances adds a new element with a specified keyand value to thisWeakMap.

Try it

const weakmap1 = new WeakMap();const object1 = {};const object2 = {};weakmap1.set(object1, "foo");weakmap1.set(object2, "bar");console.log(weakmap1.get(object1));// Expected output: "foo"console.log(weakmap1.get(object2));// Expected output: "bar"

Syntax

set(key, value)

Parameters

key: Must be either an object or anon-registered symbol. The key of the entry to add to theWeakMap object.
value: Any value representing the value of the entry to add to theWeakMap object.

Return value

TheWeakMap object.

Exceptions

TypeError: Thrown ifkey is not an object or anon-registered symbol.

Examples

Using the set() method

const wm = new WeakMap();const obj = {};// Add new elements to the WeakMapwm.set(obj, "foo").set(window, "bar"); // chainable// Update an element in the WeakMapwm.set(obj, "baz");// Using a non-registered symbol as keyconst sym = Symbol("foo");wm.set(sym, "baz");wm.set(Symbol.iterator, "qux");