Tuesday, 16 January, 2018 UTC


Create React App is great, but the projects it generates don’t have Hot Module Replacement (HMR) set up by default.
But! Create React App projects can support HMR! You just need to add a tiny bit of code to your app.
Here’s what to do:
Add 3 Lines of Code
Here’s the untouched index.js file provided by Create React App:
import React from "react"; import ReactDOM from "react-dom"; import "./index.css"; import App from "./App"; import registerServiceWorker from "./registerServiceWorker"; ReactDOM.render(<App />, document.getElementById("root")); registerServiceWorker(); 
At the bottom, add this code:
if (module.hot) { module.hot.accept(); } 
Seriously. That’s it. Have fun hot reloading!

Ready for Prime Time?

This feature is sort of hidden in the current version of Create React App. There are a few open issues regarding hot reloading on Github. Just keep in mind that it may not be 100% perfect, and if anything seems awry, just refresh the page 👍

Got Redux?

If you’re using Redux in your app, you’ll need to explicitly hot-reload the reducers. You can put this chunk of code wherever you create your store, something like this:
import { createStore } from 'redux'; import rootReducer from '../yourRootReducer'; const store = createStore(rootReducer, /* etc ... */); // Add this chunk of code: if (process.env.NODE_ENV !== 'production' && module.hot) { // Note! Make sure this path matches your rootReducer import exactly // Does not play well with "NODE_PATH" aliasing. module.hot.accept('../yourRootReducer', () => { const newRootReducer = require('../yourRootReducer').default; store.replaceReducer(newRootReducer); }); } 
Enjoy Fast Refreshes
That’s all there is to it!
Hot Reloading in Create React App Without Ejecting was originally published by Dave Ceddia at Dave Ceddia on January 15, 2018.