如何将promise的结果保存到变量中? [英] How to save results of a promise to a variable?

问题描述

我需要从API提取一些JSON数据并将结果分配给变量.我可以在控制台中看到数据数组，但是[abc]始终设置为Pending promise.

I need to fetch some JSON data from an API and assign the result to a variable. I can see the array of data in the console, but [abc] is always set as a Pending promise.

我尝试分配[abc]而不是记录[data]或仅返回[data]，但是它不起作用. 理想情况下，我也想停止执行以下代码，直到获得所需的数据为止，但是使用我拥有的代码，文本会在数据之前记录下来

I've tried to assign [abc] instead of logging [data] or simply returning [data] but it's not working. Ideally, I would also want to stop the execution of the following code until I get the required data but with the code I have, the text gets logged before the data

async function fetchData() 
{
  let response = await fetch('API');
  let data = await response.json();
  data = JSON.stringify(data);
  data = JSON.parse(data);
  return data;
}

let abc = await fetchData()
  .then(data => console.log(data)); 

console.log('This should not be logged if 'abc' does not have the data i need')

(data => console.log(data)).. >>这里的数据是我需要的数组，但是我不知道如何在变量上赋值.

(data => console.log(data)) ..>> here the data is the array I need but I have no idea on how to assign on a variable.

我在互联网上寻找了许多解决方案，但是找不到任何可以帮助您的东西.

I've looked for many solutions on the internet but I couldn't find anything that could help.

如果我分配: 让abc =等待fetchData() 如果没有then语句，则会引发此错误: 未捕获的SyntaxError:等待仅在异步函数中有效

If I assign: let abc = await fetchData() without the then statement it throws me this error: Uncaught SyntaxError: await is only valid in async function

如果我随后删除了await关键字，它将返回Promise而没有解决该问题.

If I then remove the await keyword it returns Promise without having it resolved.

推荐答案

为使await关键字起作用，它必须位于async函数内.因此，您需要先将代码包装在一个异步函数中，比如说一个主函数，然后再调用它.示例:

In order for await keyword to work, it must sit inside a async function. So you need to wrap your code in a async function first, let's say a main function, then call it. Example:

async function fetchData() {...}

async function main() {
  let abc = await fetchData();
  console.log(abc);
}

main();

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