How could I implement/combine our plugin/jindex.js with the mocha-like selection

The existing cypress/plugins/index.js file:

/* eslint-disable no-console */
const browserify = require('@cypress/browserify-preprocessor');
const path = require('path');
const fs = require('fs');
const { get, merge } = require('lodash');

// ***********************************************************
// This example plugins/index.js can be used to load plugins
//
// You can change the location of this file or turn off loading
// the plugins file with the 'pluginsFile' configuration option.
//
// You can read more here:
// https://on.cypress.io/plugins-guide
// ***********************************************************

// This function is called when a project is opened or re-opened (e.g. due to
// the project's config changing)

module.exports = (on, config) => {
   let customBrowserify;

   on('before:browser:launch', (browser = {}) => {
      const options = browserify.defaultOptions;
      const envPreset = options.browserifyOptions.transform[1][1].presets[0];
      options.browserifyOptions.transform[1][1].presets[0] = [
         envPreset,
         { ignoreBrowserslistConfig: true, targets: { [browser.name]: browser.majorVersion } },
      ];
      customBrowserify = browserify(options);
   });

   on('file:preprocessor', file => customBrowserify(file));

   const env = get(config, ['env', 'ourEnv'], 'local');
   let newConfig = config;
   const envConfigPath = path.resolve(__dirname, '../config/', `${env}.json`);
   if (fs.existsSync(envConfigPath)) {
      // eslint-disable-next-line global-require,import/no-dynamic-require
      const envConfig = require(envConfigPath);
      console.log(`Using ${env} env config:`, JSON.stringify(envConfig, null, 2));
      newConfig = merge(config, envConfig);
   } else {
      console.error('ERROR: Could not find config file:', envConfigPath);
   }

   console.log('CONFIG:', JSON.stringify(newConfig, null, 2));
   return newConfig;
};

How should i construct the above with the mocha-like selection:

const selectTestsWithGrep = require('../../grep')
module.exports = (on, config) => {
  on('file:preprocessor', selectTestsWithGrep(config))
}

bahmutov / cypress-select-tests

How could I implement/combine our plugin/jindex.js with the mocha-like selection #33