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WeakSet.prototype.add()

The add() method appends a new object to the end of a WeakSet object.

Try it

Syntax

add(value)

Parameters

value

Required. The object to add to the WeakSet collection.

Return value

The WeakSet object.

Examples

Using add

const ws = new WeakSet();

ws.add(window); // add the window object to the WeakSet

ws.has(window); // true

// WeakSet only takes objects as arguments
ws.add(1);
// results in "TypeError: Invalid value used in weak set" in Chrome
// and "TypeError: 1 is not a non-null object" in Firefox

Specifications

Specification
ECMAScript Language Specification
# sec-weakset.prototype.add

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet Deno Node.js
add
36
12
34
No
23
9
37
36
34
24
9
3.0
1.0
0.12.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet/add