text: c3_chart_fn.x = function (x) {
      var $$ = this.internal;
      if (arguments.length) {
          $$.updateTargetX($$.data.targets, x);
          $$.redraw({withUpdateOrgXDomain: true, withUpdateXDomain: true});
      }
      return $$.data.xs;
  };
  c3_chart_fn.xs = function (xs) {
      var $$ = this.internal;
      if (arguments.length) {
          $$.updateTargetXs($$.data.targets, xs);
          $$.redraw({withUpdateOrgXDomain: true, withUpdateXDomain: true});
      }
      return $$.data.xs;
  };
  