code: function (point) {
          var nthX = Math.floor((point[0] - this._rect.x) / this._sw) + 1;
          var nthY = Math.floor((point[1] - this._rect.y) / this._sh) + 1;
          var range = this._rangeInfo.range;
  
          if (this._orient === 'vertical') {
              return this._getDateByWeeksAndDay(nthY, nthX - 1, range);
          }
  
          return this._getDateByWeeksAndDay(nthX, nthY - 1, range);
      }
docs: Convert a (x, y) point to time date
  
  @param  {Array} point point
  @return {Object}       date