用列表向所有人承诺 [英] promise all with list

问题描述

我正在尝试将 promise all 与两个列表一起使用，但没有获得所需的值:

I'm trying to use promise all with two list, and I'm not getting the desired values:

只有一个列表就行了:

this.firstService.getAll()
  .then(dataR => {
      //dataR = ['data':{'data1': 'one-one', 'data2': 'one-two'},
      //   'data':{'data1': 'two-one', 'data2': 'two-two'}]
      return Promise.all(
        dataR.data1.map(x =>
          this.secondService.getReadURL(
            x.one))
    }
  ).then(dataR2 => {
     //dataR2 is a list of strings
  });

现在我正在尝试使用 data2 添加第二个 promise 调用:

Now I'm trying to add a second call in promise with data2:

 return Promise.all(
        [dataR.data.map(x =>
          this.secondService.getReadURL(
            x.data1)),
        dataR.data.map(x =>
          this.secondService.getReadURL(
            x.data2))]

    }
  ).then(dataR2 => {
     //dataR2 is a list of list of zoneAwarePRomise
  });

如何获取字符串列表的 lis?

How can I get lis of list of strings?

推荐答案

试试这个，Promise.all 接受一个promise数组[promise]，但是你发送的是[[promise],[承诺]].

try this, Promise.all accept an array of promise [promise], but you are sending [[promise],[promise]].

var promises = dataR.data.map(x =>
    this.secondService.getReadURL(
        x.data1));

promises = promises.concat(dataR.data.map(x =>
    this.secondService.getReadURL(
        x.data2)));

return Promise.all(promises).then(data => {});

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