WeakMap.prototype.delete()

Baseline Widely available

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

The delete() method of WeakMap instances removes the specified element from this WeakMap.

Try it

const weakmap1 = new WeakMap();
const object1 = {};
weakmap1.set(object1, 42);
console.log(weakmap1.delete(object1));
// Expected output: true
console.log(weakmap1.has(object1));
// Expected output: false

Syntax

js
weakMapInstance.delete(key)

Parameters

key

The key of the element to remove from the WeakMap object.

Return value

true if an element in the WeakMap object has been removed successfully. false if the key is not found in the WeakMap. Always returns false if key is not an object or a non-registered symbol.

Examples

Using the delete() method

js
const wm = new WeakMap();
wm.set(window, "foo");
wm.delete(window); // Returns true. Successfully removed.
wm.has(window); // Returns false. The window object is no longer in the WeakMap.

Specifications

Specification
ECMAScript® 2026 Language Specification
# sec-weakmap.prototype.delete

Browser compatibility

See also