Syntax

new Map()
new Map(iterable)

Note: Map() can only be constructed with new. Attempting to call it without new throws a TypeError.

Parameters

iterable Optional

If an iterable object (such as an array) is passed, all of its elements will be added to the new Map. Each element must be an object with two properties: 0 and 1, which correspond to the key and value (for example, [[1, "one"],[2, "two"]]). If you don't specify this parameter, or its value is null or undefined, the new Map is empty.

Examples

Creating a new Map

const myMap = new Map([
  [1, "one"],
  [2, "two"],
  [3, "three"],
]);

Specifications

Browser compatibility

See also

• Polyfill for Map in core-js
• es-shims polyfill of Map
• Set
• WeakMap
• WeakSet