Immutable.js provides a core set of data structures and APIs designed to be leveraged by other code. Often this is code within your own codebases, but there are also lots of excellent NPM modules designed to work well with Immutable.js

Transit is a serialisation format which builds on top of JSON to provide a richer set of types. It is extensible, which makes it a good choice for easily providing serialisation and deserialisation capabilities for Immutable's types.

Inspecting Immutable.js collections in Chrome's Dev Tools is awkward. You only see the internal data structure, not the logical contents. Chrome supports custom "formatters" which tells Dev Tools how to display values in the Console. This means we can display Lists, Maps and other collections naturally.

React PropType validators designed for Immutable.js.

redux-immutable is used to create an equivalent function of Redux combineReducers that works with Immutable.js state.

This plugin provides a set of Chai assertions for testing Immutable.js collections.

An efficient memoizer for functions that only receive immutable arguments. Ideal for Redux and Immutable.js collections.

Pretty printing for Immutable.js

Immutable cursors incorporating the Immutable.js API interface over a Clojure-inspired atom.

(Note: this Wiki is editable. Do you maintain an Immutable.js companion module? List it here!)