javascript instance method
Map.prototype.has()
The has() method of Map instances returns a boolean indicating whether an entry with the specified key exists in this Map or not.
Interactive exampleOpen the canonical MDN source to run this embedded demo.
const map = new Map();
map.set("bar", "foo");
console.log(map.has("bar"));
// Expected output: true
console.log(map.has("baz"));
// Expected output: false
Syntax
has(key)
Parameters
key- : The key of the entry to test for presence in the
Mapobject. Object keys are compared by reference, not by value.
- : The key of the entry to test for presence in the
Return value
Returns true if an entry with the specified key exists in the Map object; otherwise false.
Examples
Using has()
const myMap = new Map();
myMap.set("bar", "foo");
console.log(myMap.has("bar")); // true
console.log(myMap.has("baz")); // false
Specifications
SpecificationsStandards references are available on the canonical MDN page.
Browser compatibility
Browser compatibilityCompatibility data is available on the canonical MDN page.