react-app-rewired-preact/examples/configurable-overrides/custom-overides/index.js

Tweak the create-react-app webpack config(s) without using 'eject' and without creating a fork of the react-scripts

const { injectBabelPlugin } = require('react-app-rewired');

/* config-overrides.js */
module.exports = function override(config, env) {
  config = injectBabelPlugin('babel-plugin-transform-decorators-legacy', config);
  return config;
}