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The has()
method returns a boolean indicating whether an element with the specified key exists or not.
Syntax
myMap.has(key);
Parameters
- key
- Required. The key of the element to test for presence in the
Map
object.
Return value
- Boolean
- Returns
true
if an element with the specified key exists in theMap
object; otherwisefalse
.
Examples
Using the has
method
var myMap = new Map(); myMap.set("bar", "foo"); myMap.has("bar"); // returns true myMap.has("baz"); // returns false
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Map.prototype.has' in that specification. |
Standard | Initial definition. |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Map.prototype.has' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 38 | 13.0 (13.0) | 11 | 25 | 7.1 |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | No support | 38 | 13.0 (13.0) | No support | No support | 8 |
See also
Tag del documento e collaboratori
Tag:
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realityking
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