WeakMap.prototype.set()

The set() method adds a new element with a specified key and value to a WeakMap object.

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Syntax

js

set(key, value)

Parameters

key

Must be either an object or a non-registered symbol. The key of the entry to add to the WeakMap object.

value

Any value representing the value of the entry to add to the WeakMap object.

Return value

The WeakMap object.

Exceptions

TypeError

Thrown if key is not an object or a non-registered symbol.

Examples

Using the set() method

js

const wm = new WeakMap();
const obj = {};

// Add new elements to the WeakMap
wm.set(obj, "foo").set(window, "bar"); // chainable

// Update an element in the WeakMap
wm.set(obj, "baz");

// Using a non-registered symbol as key
const sym = Symbol("foo");
wm.set(sym, "baz");
wm.set(Symbol.iterator, "qux");

Specifications

Specification
ECMAScript Language Specification
# sec-weakmap.prototype.set

Browser compatibility

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See also