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 Latest Draft (ECMA-262)
The definition of 'WeakSet.prototype.has' in that specification.
Draft  

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung InternetNode.js
Basic supportChrome Full support 36Edge Full support YesFirefox Full support 34IE No support NoOpera Full support 23Safari Full support 9WebView Android Full support 37Chrome Android Full support 36Edge Mobile Full support YesFirefox Android Full support 34Opera Android Full support 23Safari iOS Full support 9Samsung Internet Android Full support Yesnodejs Full support 0.12

Legend

Full support  
Full support
No support  
No support

See also

Document Tags and Contributors

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