code: function() {
              let options = {};
  
              tap(Mix.paths.root('.babelrc'), babelrc => {
                  if (File.exists(babelrc)) {
                      options = JSON.parse(File.find(babelrc).read());
                  }
              });
  
              if (this.babelConfig) {
                  options = webpackMerge.smart(options, this.babelConfig);
              }
  
              return webpackMerge.smart(
                  {
                      cacheDirectory: true,
                      presets: [
                          [
                              'env',
                              {
                                  modules: false,
                                  targets: {
                                      browsers: ['> 2%'],
                                      uglify: true
                                  }
                              }
                          ]
                      ],
                      plugins: [
                          'transform-object-rest-spread',
                          [
                              'transform-runtime',
                              {
                                  polyfill: false,
                                  helpers: false
                              }
                          ]
                      ]
                  },
                  options
              );
          }
docs: The default Babel configuration.
  
  @type {Object}