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Version: 3.0

Custom Web Index

You may have noticed that there's no call to ReactDOM.render in your Redwood app. That's because Redwood automatically mounts the App component in web/src/App.js to the DOM. But if you need to customize how this happens, you can provide a file named index.js in web/src and Redwood will use that instead.

Setup

To make this easy, there's a setup command that'll give you the file you need where you need it:

yarn rw setup custom-web-index

This generates a file named index.js in web/src that looks like this:

web/src/index.js
import ReactDOM from 'react-dom'

import App from './App'
/**
* When `#redwood-app` isn't empty then it's very likely that you're using
* prerendering. So React attaches event listeners to the existing markup
* rather than replacing it.
* https://reactjs.org/docs/react-dom.html#hydrate
*/
const rootElement = document.getElementById('redwood-app')

if (rootElement.hasChildNodes()) {
ReactDOM.hydrate(<App />, rootElement)
} else {
ReactDOM.render(<App />, rootElement)

This's actually the same file Redwood uses internally. So even if you don't customize anything, things still work the way they did.