/* DEFAULT */
module.exports = function override(config, env) {
  /* Modify the config as needed*/
  return config;
};
/* ALTERNATIVE */
/*
module.exports = {
  webpack: function (config, env) {
    return config;
  },
  jest: function (config) {
    return config;
  }
}
*/
/* DEFAULT */
module.exports = function override(config, env) {
  /* Modify the config as needed*/
  return config;
};
/* ALTERNATIVE */
/*
module.exports = {
  webpack: function (config, env) {
    return config;
  },
  jest: function (config) {
    return config;
  },
  // configFunction is the original react-scripts function that creates the
  // Webpack Dev Server config based on the settings for proxy/allowedHost.
  // react-scripts injects this into your function (so you can use it to
  // create the standard config to start from), and needs to receive back a
  // function that takes the same arguments as the original react-scripts
  // function so that it can be used as a replacement for the original one.
  devServer: function (configFunction) {
    return function(proxy, allowedHost) {
      const config = configFunction(proxy, allowedHost);
      // Edit config here - example: set your own certificates.
      //
      // const fs = require('fs');
      // config.https = {
      //   key: fs.readFileSync(process.env.REACT_HTTPS_KEY, 'utf8'),
      //   cert: fs.readFileSync(process.env.REACT_HTTPS_CERT, 'utf8'),
      //   ca: fs.readFileSync(process.env.REACT_HTTPS_CA, 'utf8'),
      //   passphrase: process.env.REACT_HTTPS_PASS
      // };
      
      return config;
    };
  }
}
*/

Add example webpackDevServer config override.
Add example webpackDevServer config override.

Add an example showing how to use the devServer field to provide an override function for creating the config for the webpackDevServer in development.