Map.prototype.has()

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

{{InteractiveExample("JavaScript Demo: Map.prototype.has()")}}

```js interactive-example 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

```js-nolint
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#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Map")}}
• {{jsxref("Map.prototype.delete()")}}
• {{jsxref("Map.prototype.get()")}}
• {{jsxref("Map.prototype.set()")}}