The has() method of Map instances returns a boolean indicating whether an entry with the specified key exists in this Map or not.

Try it

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 Map object. Object keys are compared by reference, not by value.

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

Browser compatibility

See also

• Map
• Map.prototype.delete()
• Map.prototype.get()
• Map.prototype.set()