axios.get().then() 在 for 循环中 [英] Axios.get().then() in a for loop

问题描述

我将如何在 for 循环中运行 Axios，每个循环都有相应的 .then() 函数.然后在 for 循环结束后，运行另一个函数.

How would I go about running Axios in a for loop, each with a corresponding .then() function. Then after the for loop ends, run another function.

示例:

const array = ['asdf', 'foo', 'bar'];
let users = [];
for (i = 0; i < array.length; i++) {
  axios.get('/user/' + array[i].id).then(response => {
    // do something with response
    users.push(response);
  });
}

console.log(users);

推荐答案

const array = [{ id: 'asdf'}, { id: 'foo' }, { id: 'bar' }]; // changed the input array a bit so that the `array[i].id` would actually work - obviously the asker's true array is more than some contrived strings
let users = [];
let promises = [];
for (i = 0; i < array.length; i++) {
  promises.push(
    axios.get('/user/' + array[i].id).then(response => {
      // do something with response
      users.push(response);
    })
  )
}

Promise.all(promises).then(() => console.log(users));

Promise 本身的 .then() 方法返回一个 Promise；所以你可以收集这些并使用 Promise.all() 等待所有它们.

The .then() method of a Promise itself returns a Promise; so you can collect those and await all of them with Promise.all().

请注意，即使您在 async 函数中执行此操作，您也不希望在 for 循环内 await，因为这样每个请求都会等待让前一个在它开始之前完成，并且大概您想并行运行这些请求.

Note that even if you're doing this within an async function, you don't want to await inside the for-loop, because then each request will wait for the previous one to finish before it even starts, and presumably you want to run these requests in parallel.

根据您的用例，简洁的 async/await 函数可能如下所示:

Depending on your use case, a concise async / await function might look like this:

async function getMultiple(...objectsToGet) {
  let users = [];
  await Promise.all(objectsToGet.map(obj =>
    axios.get('/user/' + obj.id).then(response => {
      // do something with response
      users.push(response);
    })
  ));
  return users;
}

// some other async context
console.log(await getMultiple({ id: 'asdf'}, { id: 'foo' }, { id: 'bar' }));

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