Map.prototype.has()

The has() method returns a boolean indicating whether an element with the specified key exists or not.

Syntax

myMap.has(key)

Parameters

key
The key of the element to test for presence in the Map object.

Return value

true if an element with the specified key exists in the Map object; otherwise false.

Examples

Using has()

let myMap = new Map()
myMap.set('bar', "foo")

myMap.has('bar')   // returns true
myMap.has('baz')   // returns false

Specifications

Specification
ECMAScript (ECMA-262)
The definition of 'Map.prototype.has' in that specification.

Browser compatibility

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See also