小程序商城--将商品加入购物车缓存

js代码：

  //添加购物车事件方法  toCart: function (event) {    //判断是否选中规格    this.checkInfo();    if (!this.data.chooseInfoFlag) {      wx.showModal({        title: '提示',        content: '请选择规格',        showCancel: false,        success:{}      })    }     else {      //创建动画      var animation = wx.createAnimation({        duration: 100,        timingFunction: 'ease-in-out'      });      this.animation = animation;      animation.translateY(-336).step();      this.setData({        animationData: this.animation.export(),        maskVisual: 'show'      });      //将购物车数据添加到缓存      var that = this      //获取缓存中的已添加购物车信息      var cartItems = wx.getStorageSync('cartItems') || []      console.log(cartItems)      //判断购物车缓存中是否已存在该货品      var exist = cartItems.find(function (ele) {        return ele.id === that.data.goodsInfoId      })      console.log(exist)      if (exist) {        //如果存在，则增加该货品的购买数量        exist.quantity = parseInt(exist.quantity) + that.data.buyCount      } else {        //如果不存在，传入该货品信息        cartItems.push({          id: that.data.goodsInfoId,          quantity: that.data.buyCount,          price: that.data.goodsInfoPrice,          title: that.data.goodsVo.goodsName,          goodsPicsInfo: that.data.goodsInfoImg        })      }      //加入购物车数据，存入缓存      wx.setStorage({        key: 'cartItems',        data: cartItems,        success: function (res) {          //添加购物车的消息提示框          wx.showToast({            title: "添加购物车",            icon: "success",            durantion: 2000          })        }      })    }  }