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

metadata

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

The get() method of {{jsxref("Map")}} instances returns the value corresponding to the key in this Map, or undefined if there is none. Object values are returned as the same reference that was originally stored, not as a copy, so mutations to the returned object will be reflected anywhere that reference is held, including inside the Map.

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

const map = new Map();
map.set("bar", "foo");

console.log(map.get("bar"));
// Expected output: "foo"

console.log(map.get("baz"));
// Expected output: undefined

Syntax

get(key)

Parameters

• key
  • : The key of the value to return from the Map object. Object keys are compared by reference, not by value.

Return value

The value associated with the specified key in the Map object. If the key can't be found, {{jsxref("undefined")}} is returned.

Examples

Using get()

const myMap = new Map();
myMap.set("bar", "foo");

console.log(myMap.get("bar")); // Returns "foo"
console.log(myMap.get("baz")); // Returns undefined

Using get() to retrieve a reference to an object

const arr = [];
const myMap = new Map();
myMap.set("bar", arr);

myMap.get("bar").push("foo");

console.log(arr); // ["foo"]
console.log(myMap.get("bar")); // ["foo"]

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

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