小程序多层循环嵌套导致加载慢

使用循环的时候有的需要多次循环列表找到最终需要的数据，但是会导致接口以及页面加载缓慢，此时建议将循环单独取出，并发触发循环，而不是循环完一个再循环下一个
正确实例

let obj = this.data.myDefaultCar;      let setId = '';      let arry1 = [];      let arry2 = [];      if (this.data.myDefaultCar) {        this.setData({          curClass: {            gcName: obj.zichexi,            scName: obj.brandName,            gcId: ''          },        })        let newList = this.data.carArr;        newList.forEach(item = { // 循环使列表滑动指定位置          let newObj = item.brands          for (var k in newObj) {              if (newObj[k].brandName === this.data.myDefaultCar.brandName) {                this.setData({                  toView: 'a_' + k,                  setId: newObj[k].brandId,                  arry1: item.brands                })                // console.log(k + '在数组中出现的位置为' + this.data.toView);              }          }        });        this.data.arry1.forEach(res = { // 循环使列表对应车型厂商展开          if (res.brandId == this.data.setId) {            res.childShow = !res.childShow;          } else {            res.childShow = true;          }          this.setData({            carArr: newList,            arry2: res.factoryList          });          return true;        })        this.data.arry2.forEach(respone = { // 循环出厂商id进行搜索类表          if (respone.factoryName == this.data.myDefaultCar.zichexi) {            this.setData({              factoryid: respone.factoryid            })          }        });        this.getStoreGoods()      }

错误实例

let obj = this.data.myDefaultCar      let setId = ''      if (this.data.myDefaultCar) {        this.setData({          curClass: {            gcName: obj.zichexi,            scName: obj.brandName,            gcId: ''          },        })        let newList = this.data.carArr;        newList.forEach(item = {          let newObj = item.brands          for (var k in newObj) {              if (newObj[k].brandName === this.data.myDefaultCar.brandName) {                console.log('*****',newObj[k].brandId)                this.setData({                  toView: 'a_' + k,                  setId: newObj[k].brandId                })                console.log(k + '在数组中出现的位置为' + this.data.toView);              }          }          newObj.forEach(res = {            if (res.brandId == this.data.setId) {              res.childShow = !res.childShow;            } else {              res.childShow = true;            }            this.setData({              carArr:newList            });            return true;            if (res.brandName == this.data.myDefaultCar.brandName) {              this.setData({                CarParentId: res.brandId              })              res.factoryList.forEach(respone = {                if (respone.factoryName == this.data.myDefaultCar.zichexi) {                  this.setData({                    factoryid: respone.factoryid                  })                }              });            }          })        });        this.getStoreGoods()      }

这两种加载速度有天壤之别，以后要注意了