The has() method returns a boolean indicating whether an object exists in a WeakSet or not.
ws.has(value);
WeakSet.true if an element with the specified value exists in the WeakSet object; otherwise false.has methodvar ws = new WeakSet();
var obj = {};
ws.add(window);
mySet.has(window); // returns true
mySet.has(obj); // returns false
| 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 |
| Desktop | ||||||
|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
| Basic support | 36 | Yes | 34 | No | 23 | 9 |
| Mobile | |||||||
|---|---|---|---|---|---|---|---|
| Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
| Basic support | 37 | 36 | Yes | 34 | 23 | 9 | Yes |
| Server | |
|---|---|
| Node.js | |
| Basic support | 0.12 |
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet/has