multireducer

multireducer is a utility to wrap many copies of a single Redux reducer into a single key-based reducer.

Installation

npm install --save multireducer

Why?

There are times when writing a Redux application where you might find yourself needing multiple copies of the same reducer. For example, you might need more than one list of the same type of object to be displayed. Rather than make a big reducer to handle list A, B, and C, and have action creators either in the form addToB(item) or addToList('B', item), it would be easier to write one "list" reducer, which is easier to write, reason about, and test, with a simpler add(item) API.
However, Redux won't let you do this:

import list from './reducers/list';

const reducer = combineReducers({
  a: list,		// WRONG
  b: list,		// WRONG
  c: list		// WRONG
});

Each of those reducers is going to respond the same to every action.
This is where multireducer comes in. Multireducer lets you mount the same reducer any number of times in your Redux state tree, as long as you pass the key that you mounted it on to your connected component.
Read the full API Documentation

Working Example

The react-redux-universal-hot-example project uses multireducer. See its reducer.js, which combines the plain vanilla counter.js duck, to a multireducer. The CounterButton.js connects to the multireducer, and the Home.js calls <CounterButton/> with a multireducerKey prop.
Example with multiple counters and ducks composition.