code: function propsStream(options) {
      if (!_.isObject(options)) {
          options = {};
      }
  
      return through.obj(function(chunk, enc, cb) {
          var webpackOptions = chunk[FIELD_NAME] || {};
  
          webpackOptions = _.merge(webpackOptions, options);
  
          chunk[FIELD_NAME] = webpackOptions;
  
          cb(null, chunk);
      });
  }
docs: Overrides existing properties of each `webpack.config.js` file. Can be piped.
  @function
  @alias propsStream
  @param {Configuration=} options
  @returns {Stream}