I created a react application using create-react-app boilerplate, which seems to be very popular, hot reload some times updates when any of the files changes and some times
Apparently hot module reloading only works out-of-the-box if you eject your app.
But if you haven't ejected your app, then you can follow these instructions to get it working.
Find the ReactDOM.render(...) at the top of your app, and add these lines below it:
ReactDOM.render(...);
if (module.hot) {
module.hot.accept('./App', () => {
// --- Copy-paste your usual ReactDOM.render(...) call here: --- //
ReactDOM.render(...);
});
}
The instructions linked above also show how to hot reload things outside of the component tree, such as redux reducers.