Immutable.js - Immutable collections for JavaScript

Immutable data cannot be changed once created, leading to much simpler application development, no defensive copying, and enabling advanced memoization and change detection techniques with simple logic. Persistent data presents a mutative API which does not update the data in-place, but instead always yields new updated data. Immutable.js provides many Persistent Immutable data structures including: List, Stack, Map, OrderedMap, Set, OrderedSet and Record.

Immutable.js has no dependencies, which makes it predictable to include in a Browser. Immutable.js is inspired by Clojure, Scala, Haskell and other functional programming environments, it's designed to bring these powerful concepts to JavaScript, and therefore has an Object-Oriented API that closely mirrors that of ES2015 Array, Map, and Set.