Breaking out of Redux paradigm to isolate apps

index.js

import React, { Component } from 'react'
import Subapp from './subapp/Root'

class BigApp extends Component {
  render() {
    return (
      <div>
        <Subapp />
        <Subapp />
        <Subapp />
      </div>
    )
  }
}

// These subapps will be completely independent.
//
// They won't share data or actions, and won't see or communicate with each other.
// If you mix this approach with standard Redux approach of composing reducers, it
// will get extremely confusing so it's best if you pick just one: either your app
// is composed of pieces that follow Redux pattern holistically, or your app is so
// large and disjointed that smaller independent "subapps" make more sense.
//
// The first case is probably closer to normal web products, and the second case is
// closer to a "product hub", a "dashboard", or enterprise software where unrelated
// tools are grouped together because they're part of one package.

subapp-App.js

// This is our subapp's root connected component.
// It can render more components, connected or not, below, just like normally.
// Usually we'd render it in <Provider> and be done with it.

class App extends Component { ... }
export default connect(mapStateToProps)(App)

subapp-index.js

// However we don't have to call ReactDOM.render(<Provider><App /></Provider>)
// if we're interested in hiding the fact that it's a Redux app.
//
// Maybe we want to be able to run multiple instances of it in the same "bigger" app
// and keep it as a complete black box, with Redux being an implementation detail.
// To hide Redux behind a React API, we can wrap it in a special component that
// initializes the store in the constructor. This way every instance will be independent.
//
// Note that this is *not* recommended for parts of the same app that share data.
// But it can be useful when the bigger app has zero access to smaller apps' internals,
// and we'd like to keep the fact that they are implemented with Redux an implementation detail.
// Each component instance will have its own store, so they won't "know" about each other.

import React, { Component } from 'react'
import { Provider } from 'react-redux'
import reducer from './reducers'
import App from './App'

class Root extends Component {
  constructor(props) {
    super(props)
    this.store = createStore(reducer)
  }
  
  render() {
    return (
      <Provider store={this.store}>
        <App />
      </Provider>
    )
  }
}

Nice Work Dan

nice, but how will DevTools work if there are 3 instances of the same app which may all use the same devtool?

@slorber if you use the Chrome extension you'd have to instrument it in each store, but theoretically that should work. It's already capable of keeping track of stores in different tabs simultaneously.

thanks :) didn't know that as I don't use redux devtools yet unfurtunatly

@StevenLangbroek, yes, that would work, also you could name each subapp instance and easily switch between them.

FYI: following the example, if you also need to wrap the root application component (e.g. BigApp) into a Provider, you have then a problem the SubApps also have Providers.
As you may guess, the problem is that the stores in the context will conflict as they have the same name store.

To solve that, based on Dan's feedback, I've put together a small library that allows you to define a custom store name, effectively allowing to have nested providers.

https://github.com/emmenko/react-redux-custom-store

Thanks for this nice Gist! But I wonder how to dispatch actions to the component's own special store? Is there a way to access the store-prop of the <Provider /> for each <SubApp /> (and their child-components)?

Which approach would someone take if each 'subapp' is rendered in a separate page instead of nested in a parent div?