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WeakMap.prototype.get()

The get() method of WeakMap instances returns a specified element from this WeakMap.

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Syntax

get(key)

Parameters

key: The key of the element to return from the WeakMap object.

Return value

The element associated with the specified key in the WeakMap object. If the key can't be found, undefined is returned. Always returns undefined if key is not an object or a non-registered symbol.

Examples

Using the get() method

const wm = new WeakMap();
wm.set(window, "foo");

wm.get(window); // Returns "foo".
wm.get("baz"); // Returns undefined.

Specifications

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

Browser compatibility

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`get`	36	12	6 Before Firefox 38, this method threw a `TypeError` when the key parameter was not an object. However, the ES2015 specification specifies to return `undefined` instead. Furthermore, `WeakMap.prototype.get` accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher.	23	8	36	6 Before Firefox 38, this method threw a `TypeError` when the key parameter was not an object. However, the ES2015 specification specifies to return `undefined` instead. Furthermore, `WeakMap.prototype.get` accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher.	24	8	3.0	37	1.0	0.12.0