code: function getCenter(touches) {
        var valuesX = [], valuesY = [];
  
        for(var t= 0,len=touches.length; t<len; t++) {
          valuesX.push(touches[t].pageX);
          valuesY.push(touches[t].pageY);
        }
  
        return {
          pageX: ((Math.min.apply(Math, valuesX) + Math.max.apply(Math, valuesX)) / 2),
            pageY: ((Math.min.apply(Math, valuesY) + Math.max.apply(Math, valuesY)) / 2)
        };
      }
docs: get the center of all the touches
  @param   {Array}     touches
  @returns {Object}    center