Redux Hub Middleware

This Redux middleware's purpose is to allow actions dispatched on multiple stores at once It is likely to be used in large React/Redux-based projects having multiple sub-apps having own and isolated stores:

<WrapperOrRouterSetup>
    <AppFirst/>{/* which has own store */}
    <AppSecond/>{/* which has another store */}
</WrapperOrRouterSetup>

Let's say AppFirst needs to share data with AppSecond. Then we need this data placed on higher level. One of the solutions is to connect Redux stores to the hub:

import { createStore, applyMiddleware } from 'redux';
import createReduxHub from 'redux-hub-middleware';

const hub = createReduxHub();

function reducer1(state = 'store1 initial', action) {
  if (action.type === 'CHANGE') {
    return action.value;
  }
  
  return state;
}

function reducer2(state = 'store2 initial', action) {
  if (action.type === 'CHANGE') {
    return action.value;
  }
  
  return state;
}

const store1 = createStore(reducer1, applyMiddleware(hub.middleware));

const store2 = createStore(reducer2, applyMiddleware(hub.middleware));

hub.connect(store1);
hub.connect(store2);

store1.dispatch({type: 'CHANGE', value: 'foo'});
store2.getState(); // returns 'foo'

store2.dispatch({type: 'CHANGE', value: 'bar'});
store1.getState(); // returns 'bar'

A newly created hub could be passed to appliction components for later use:

import React from 'react';

import createReduxHub from 'redux-hub-middleware';

const hub = createReduxHub();

React.render(
    <WrapperOrRouterSetup>
        <AppFirst reduxHub={hub}/>{/* hub is passed as prop to use it later in store initialization */}
        <AppSecond reduxHub={hub}/>
    </WrapperOrRouterSetup>,
    root
)

API

The library exposes createReduxHub function which takes no arguments and returns new hub instance containing connect and middleware functions:

const { connect, middleware } = createReduxHub();

middleware function must be added to middleware list when a store is created:

import { createStore, applyMiddleware } from 'redux';
import createReduxHub from 'redux-hub-middleware';

const { connect, middleware } = createReduxHub();

const store = createStore(reducer, applyMiddleware(middleware));

connect function is used to connect stores to a hub:

import { createStore, applyMiddleware } from 'redux';
import createReduxHub from 'redux-hub-middleware';

const { connect, middleware } = createReduxHub();

const store = createStore(reducer, applyMiddleware(middleware));

connect(store);

After connection all actions dispatched in one store will be re-dispatched on all other connected stores.