code: function (points) {
          var total = 0;
          for (var i = 0; i < points.length - 1; i++) {
              total += this.distance(points[i], points[i + 1]);
          }
          return total;
      }
docs: Given a line (an array of points), returns the total line distance.
  
  @param {Array<Array<number>>} points [longitude, latitude]
  @returns {number} total line distance
  @example
  var length = ruler.lineDistance([
  [-67.031, 50.458], [-67.031, 50.534],
  [-66.929, 50.534], [-66.929, 50.458]
  ]);
  //=length