Loading the hot module (https://github.com/gaearon/react-hot-loader) is a method of updating code in the React/Redux project without having to refresh the page. This means code changes will be automatically applied when we save a file without a full browser refresh. To set up the react-hot-loader module, follow these steps:

1. Install react-hot-loader:

yarn add react-hot-loader@next --dev --exact
or
npm install --save-dev react-hot-loader@next

2. Add it to the Babel file. In our case, we are using babel.config.js:

{
  "plugins": ["react-hot-loader/babel"]
}

3. Make the root component hot-exported:

import { hot } from 'react-hot-loader/root'
const App = () => <div>Hello World!</div>
export default hot(App)

4. Run webpack with hot module replacement:

webpack-dev-server --hot