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.
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 Same-value-zero
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
Browser compatibility
BCD tables only load in the browser