The has()
method returns a boolean indicating whether an element with the specified value exists in a Set
object or not.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
Syntax
mySet.has(value);
Parameters
value
- The value to test for presence in the
Set
object.
Return value
Returns true
if an element with the specified value exists in the Set
object; otherwise false
.
Note: Technically speaking, has()
uses the sameValueZero
algorithm to determine whether the given element is found.
Examples
Using the has
method
var mySet = new Set(); mySet.add('foo'); mySet.has('foo'); // returns true mySet.has('bar'); // returns false var set1 = new Set(); var obj1 = {'key1': 1}; set1.add(obj1); set1.has(obj1); // returns true set1.has({'key1': 1}); // returns false because they are different object references set1.add({'key1': 1}); // now set1 contains 2 entries
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Set.prototype.has' in that specification. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
has | Chrome Full support 38 | Edge Full support 12 | Firefox Full support 13 | IE Full support 11 | Opera Full support 25 | Safari Full support 8 | WebView Android Full support 38 | Chrome Android Full support 38 | Firefox Android Full support 14 | Opera Android Full support 25 | Safari iOS Full support 8 | Samsung Internet Android Full support 3.0 | nodejs
Full support
0.12
|
Legend
- Full support
- Full support
- User must explicitly enable this feature.
- User must explicitly enable this feature.