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WeakSet.prototype.has()

The has() method returns a boolean indicating whether an object exists in a WeakSet or not.

Syntax

ws.has(value);

Parameters

value
Required. The object to test for presence in the WeakSet.

Return value

Boolean
Returns true if an element with the specified value exists in the WeakSet object; otherwise false.

Examples

Using the has method

var ws = new WeakSet();
var obj = {};
ws.add(window);

mySet.has(window);  // returns true
mySet.has(obj);     // returns false

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'WeakSet.prototype.has' in that specification.
Standard Initial definition.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'WeakSet.prototype.has' in that specification.
Draft  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 36 34 (34) No support 23 No support
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support 34.0 (34) No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: fscholz, realityking, teoli
 Last updated by: fscholz,