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
trueif an element with the specified value exists in theWeakSetobject; otherwisefalse.
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
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 36 | (Yes) | 34 (34) | No support | 23 | No support |
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | No support | (Yes) | 34.0 (34) | No support | No support | No support |