递归调用异步API调用 [英] Recursively calling an asynchronous API call

问题描述

我正在尝试从API中获取数据，该API每次调用仅返回1000个项目，我想递归地执行此操作，直到获得所有数据为止.

I'm trying to fetch data from an API that only returns 1000 items per call, and I want to do this recursively until I have all the data.

我事先不知道总共有多少个项目，所以每次通话后我都必须检查

I don't know beforehand how many items there are in total, so after every call I have to check

如果通话是同步的，我会使用类似以下的内容:

If the call was synchronous, I'd use something like this:

function fetch(all, start) {
    const newData = getData(start, 1000);
    all = all.concat(newData);
    return (newData.length === 1000) ? fetch(all, all.length) : all;
}

但是，这里的getData()调用是异步的.使用Promise.all()无效，因为我事先不知道需要多少个电话，所以我无法准备一系列电话.

However, the getData() call here is asynchronous. Using a Promise.all() doesn't work because I don't know beforehand how many calls I need so I can't prepare an array of calls.

我有种可以使用生成器或async/await解决此问题的感觉，但我不知道如何解决.谁能指出我正确的方向?

I have the feeling I could solve this with generators or with async/await but I don't know how. Can anyone point me in the right direction?

以防万一，我使用的是Angular 4.

In case it makes a difference, I'm using Angular 4.

推荐答案

这取决于您的情况.考虑到getData返回一个诺言，它是:

This depends on how things are done in your case. Considering that getData returns a promise, it is:

async function fetch(all, start) {
    const newData = await getData(start, 1000);
    all = all.concat(newData);
    return (newData.length === 1000) ? await fetch(all, all.length) : all;
}

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