Dec 8, 2025 · The Map object holds key-value pairs and remembers the original insertion order of the keys. Any value (both objects and primitive values) may be used as either a key or a value.

A JavaScript Map is an object that can store collections of key-value pairs, similar to a dictionary in other programming languages. Maps differ from standard objects in that keys can be of any data type.

Feb 11, 2013 · The purpose of the function is to take an object and modify the original contents of the object using a method available to all objects (objects and arrays alike) without returning an array.

This tutorial introduces you to the JavaScript Map object and shows you how to manipulate maps effectively.

A Map is a built in object that holds key-value pairs. It can hold a key of any data type unlike in plain objects. It maintains the insertion order and provides helpers to manage key-value pairs.

Sep 23, 2025 · A JavaScript Map holds key-value pairs and similar to Hash Map or Dictionary in other languages. Preserves the original insertion order. Supports any type, including objects and …

Feb 21, 2024 · Map and Set are two JavaScript data structures you can use to store a collection of values, similar to Objects and Arrays. They are specialized data structures that can help you store …

Feb 6, 2025 · A comprehensive guide to the JavaScript Map object, covering its properties, methods, and practical usage with clear examples.

If you write modern JavaScript (or TypeScript), you’ll reach for key-value storage constantly: grouping results, counting events, caching expensive calls, indexing by id, tracking unique objects, or building …

Nov 14, 2022 · If we have a plain object, and we’d like to create a Map from it, then we can use built-in method Object.entries (obj) that returns an array of key/value pairs for an object exactly in that format.