NodeJS 获取承诺回调挂起 [英] NodeJS fetch promise callback pending

问题描述

我有这个代码:

fetch(url).then(response => {const json = response.json();console.log('最简单的获取', json, json.where);});

在控制台中我得到:

 最简单的获取 Promise {[[PromiseStatus]]: "pending", [[PromiseValue]]: undefined} undefined

我大部分都会得到这个.有时我会获得成功"状态.对我来说，这意味着在 fetch 承诺解决之前正在运行回调.

我希望该函数仅在提取完成时运行.我该怎么做?

解决方案

response.json()返回一个promise，使用then回调来获取数据:><块引用>

Body mixin 的 json() 方法接受一个 Response 流并读取它完成.它返回一个承诺，该承诺将正文文本解析为 JSON.

fetch(url).then(response => response.json()).then(data => console.log('simplest possible fetch', data, data.where));

I have this code:

fetch(url).then(response => {
  const json = response.json();
  console.log('simplest possible fetch', json, json.where);
});

In the console I get:

simplest possible fetch Promise {[[PromiseStatus]]: "pending", [[PromiseValue]]: undefined} undefined

I get this most of the time. Sometimes I get the "success" status. To me this implies the callback is being run before the fetch promise has resolved.

I want the function to be run only when the fetch completes. How do I do this?

解决方案

response.json() returns a promise, use then callback to get the data:

The json() method of the Body mixin takes a Response stream and reads it to completion. It returns a promise that resolves with the result of parsing the body text as JSON.

fetch(url)
  .then(response => response.json())
  .then(data => console.log('simplest possible fetch', data, data.where));

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