code: function() {
  
              var points = this.points;
              var numPoints = points.length;
              if (numPoints === 0) return ''; // if points array is empty
  
              var output = '';
              for (var i = 0; i < numPoints; i++) {
  
                  var point = points[i];
                  output += point.x + ',' + point.y + ' ';
              }
  
              return output.trim();
          }
docs: Return svgString that can be used to recreate this line.