files/en-us/web/javascript/reference/global_objects/map/has/index.md

metadata

title: Map.prototype.has()
short-title: has()
slug: Web/JavaScript/Reference/Global_Objects/Map/has
page-type: javascript-instance-method
browser-compat: javascript.builtins.Map.has
sidebar: jsref

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()")}}

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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

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