dimension.js

    this.dimensions = function () {
      return _.chain(points)
        .filter(function (item) {
          if (item !== 'Z') {
            return item;
          }
        })
        .map(function (point) {
          var command = point[0];
          point = point.substr(1, point.length)
            .split(',');
          if (command !== 'Z') {
            return {
              command: command,
              x: parseInt(point[0], 10),
              y: parseInt(point[1], 10)
            };
          } else {
            return false;
          };
        })
        .sortBy(function (i) {
          return i.x + i.y;
        })
        .last()
        .value();
    }();