code: function union (a) {
                      var args = libs.object.only(libs.object.toArray(arguments), 'array');
  
                      var union = [];
                      args.unshift(a);
                      libs.object.each(args, function (array) {
                          libs.object.each(array, function (item) {
                              if(union.indexOf(item) === -1) union.push(item);
                          });
                      });
                      return union;
                  }
docs: Computes the union between the current array, and all the array objects passed in. That is,
  the set of unique objects present in all of the arrays.
  @param {Array} a The Array object to operate on.
  @param {...Array} arr A list of array objects
  @return {Array<*>} The union set of the provided arrays.