crtxdmp.

{
  …
  "scripts": {
    "start": "react-app-rewired start",
    "build": "react-app-rewired build"
  }
  …
}

module.exports = function override(config, env) {

  config.output.filename = 'widget.js';

  config.optimization.splitChunks  = {
    cacheGroups: {
      default: false,
    },
  };
  config.optimization.runtimeChunk = false;

  return config;
};

import React from 'react';
import ReactDOM from 'react-dom';
import App from 'src/app/index';

//@ts-ignore
window.myWidget = (containerElement, config) => {
  ReactDOM.render(
    <React.StrictMode>
        <App config={config} />
    </React.StrictMode>,
    containerElement
  );
};

// this should be disabled if you don't want to mount the app automatically.
// anyway this is very helpful while doing dev work
if (document.getElementById("root") !== null) {
//@ts-ignore
  window.myWidget(
    document.getElementById("root"),
    {}
  );
}