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

Syntax

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

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

Browser compatibility

See also

• WeakMap
• WeakMap.prototype.get
• WeakMap.prototype.has