code: function snapMultiple(v, base, snapType) {
      var div = void 0;
      if (snapType === 'ceil') {
        div = Math.ceil(v / base);
      } else if (snapType === 'floor') {
        div = Math.floor(v / base);
      } else {
        div = Math.round(v / base);
      }
      return div * base;
    }
docs: 获取逼近的倍数