WeakSet.prototype.has()
The has()
method returns a boolean indicating whether an object exists in a WeakSet
or not.
Syntax
JavaScript
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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 theWeakSet
object; otherwisefalse
.
Examples
Using the has
method
JavaScript
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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
License
© 2016 Mozilla Contributors
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/has