Set.prototype.has()
The has() method returns a boolean indicating whether an
element with the specified value exists in a Set object or not.
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Syntax
has(value)
Parameters
value-
The value to test for presence in the
Setobject.
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
const mySet = new Set();
mySet.add('foo');
mySet.has('foo'); // returns true
mySet.has('bar'); // returns false
const set1 = new Set();
const 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 Language Specification # sec-set.prototype.has |
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