code: function listModulesInDirectory(modulesDir) {
      const log = debug('phantomas:modules');
      log('Getting the list of all modules in ' + modulesDir);
  
      // https://nodejs.org/api/fs.html#fs_fs_readdirsync_path_options
      var ls = fs.readdirSync(modulesDir),
          modules = [];
  
      ls.forEach(function(entry) {
          // First check whether an entry is a directory, than check if it contains a module file
          // https://nodejs.org/api/fs.html#fs_fs_existssync_path
          if (fs.existsSync(modulesDir + '/' + entry + '/' + entry + '.js')) {
              modules.push(entry);
          }
      });
  
      return modules.sort();
  }
docs: Lists all modules / extensions in a given directory
  
  @param {string} modulesDir
  @returns {Array<string}