【问题标题】:returning fetching data to object in for loop js在for循环js中将获取数据返回到对象
【发布时间】:2021-12-21 12:23:23
【问题描述】:

我有一个小问题,我需要在 for 循环中加载页面时获取数据。我有一个异步函数返回result,它从服务器返回result,但它只显示在console.log() 中,但我的对象只有promise 对象。有人可以向我解释如何以正确的方式做到这一点吗?

JSON

 let a = {
        createdAt: "2021-11-06T11:03:15.917+0000",
        updatedAt: "2021-11-06T11:03:15.917+0000",
        version: 0,
        scheduleDate: "2021-09-24",
        schedule: [
          {
            date: "2021-09-24",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
          {
            date: "2021-09-25",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
          {
            date: "2021-09-26",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
          {
            date: "2021-09-27",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
          {
            date: "2021-09-28",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
          {
            date: "2021-09-29",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
          {
            date: "2021-09-30",
            breakfast: 1,
            secondBreakfast: 1,
            lunch: 1,
            dinner: 1,
            supper: 1,
            prepareTime: 55,
            calorific: 33.4,
            protein: 1.1,
            fat: 0.2,
            carbohydrates: 7.1,
            roughage: 0.4,
          },
        ],
        memberId: 1,
        id: 49,
      };
 this.parseMemberScheduleData(a);
 parseMemberScheduleData(aSchedule) {
      let arr = [];
      for (let i = 0; i < aSchedule.schedule.length; i++) {
        arr.push({
          data: aSchedule.schedule[i].date,
          meals: {
            breakfast: this.fetchMealDetails(aSchedule.schedule[i].breakfast),
            secondBreakfast: this.fetchMealDetails(
              aSchedule.schedule[i].secondBreakfast
            ),
            dinner: this.fetchMealDetails(aSchedule.schedule[i].dinner),
            lunch: this.fetchMealDetails(aSchedule.schedule[i].lunch),
            supper: this.fetchMealDetails(aSchedule.schedule[i].supper),
          },
          mealsId: {
            breakfast: aSchedule.schedule[i].breakfast,
            secondBreakfast: aSchedule.schedule[i].secondBreakfast,
            dinner: aSchedule.schedule[i].dinner,
            lunch: aSchedule.schedule[i].lunch,
            supper: aSchedule.schedule[i].supper,
          },
        });
      }

 async fetchMealDetails(aId) {
      let requestOptions = {
        method: "GET",
        redirect: "follow",
      };
      try {
        let responce = await fetch(`${MEALS}${aId}`, requestOptions);
        let result = await responce.json();
  console.log("~ result", result);
        return result;
      } catch (err) {
        console.log(err);
      }
    },

【问题讨论】:

    标签: javascript async-await fetch


    【解决方案1】:

    你得到了 Promise 返回,因为你没有 await for 循环中的结果

     async function parseMemberScheduleData(aSchedule) {
          let arr = [];
          for (let i = 0; i < aSchedule.schedule.length; i++) {
            arr.push({
              data: aSchedule.schedule[i].date,
              meals: {
                breakfast: await this.fetchMealDetails(aSchedule.schedule[i].breakfast),
                secondBreakfast: await this.fetchMealDetails(
                  aSchedule.schedule[i].secondBreakfast
                ),
                dinner: await this.fetchMealDetails(aSchedule.schedule[i].dinner),
                lunch: await this.fetchMealDetails(aSchedule.schedule[i].lunch),
                supper: await this.fetchMealDetails(aSchedule.schedule[i].supper),
              },
              mealsId: {
                breakfast: aSchedule.schedule[i].breakfast,
                secondBreakfast: aSchedule.schedule[i].secondBreakfast,
                dinner: aSchedule.schedule[i].dinner,
                lunch: aSchedule.schedule[i].lunch,
                supper: aSchedule.schedule[i].supper,
              },
            });
          }
        //I don't know the function that calls this but if this function returns everything.. you must await parseMemberScheduleData(theData)
    
    

    【讨论】:

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