CRA + WordPress. wp admin. Function plugin

index.js

import React from 'react'
import ReactDOM from 'react-dom'
import './index.css'
import App from './App'
import * as serviceWorker from './serviceWorker'

const reactAppData = window.rpReactPlugin || {}
const { appSelector } = reactAppData
const appAnchorElement = document.querySelector(appSelector)

if (appAnchorElement) {
  ReactDOM.render(
    <React.StrictMode>
      <App />
    </React.StrictMode>,
    appAnchorElement
  )
}

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister()