如何从函数中返回获取 API 结果? [英] How can I return the fetch API results form a function?

问题描述

我想从函数返回获取 API 结果.但我未定义并且该函数不返回我获取的数据:

I want to return fetch API result from a function. but I get undefined and that function doesn't return me fetched data :

function func() {
    fetch('https://randomuser.me/api/?results=10')
    .then(response => response.json())
    .then(json => (json.results))
}

let users = func()

console.log(users);

推荐答案

Fetch 是异步的并返回一个 promise.没有办法把fetch返回的数据同步访问.并且它不能返回users，因为该函数需要同步返回但users 的数据将不可用.该函数在 Fetch 收到来自 url 的响应之前返回.没关系，这就是一切完成的方式，并且仍然有效.

Fetch is asynchronous and returns a promise. There is no way to take the data returned by fetch and access it synchronously. And it can't return users because the function needs to return synchronously but the data for users won't be available. The function returns before Fetch has a response from the url. That's okay, that's how everything is done and it all still works.

最灵活的处理方式是从函数中返回promise.然后你可以在承诺的结果上使用 then() 并在那里做任何你需要做的事情:

The most flexible way to handle this is to just return the promise from the function. Then you can use then() on the result of the promise and do anything you need to do there:

function func(url) {
    return fetch(url)  // return this promise
    .then(response => response.json())
    .then(json => (json.results))
}

func('https://randomuser.me/api/?results=10')
.then(users => console.log(users))  // call `then()` on the returned promise to access users
.catch(err => /* handle errors */)

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