Question

我正在尝试从NewsAPI中提取数据-我所获得的API的结果是一个可解决的承诺，我不知道如何访问其中的对象。

///////////////////SAMPLE CODE

let raps;

var url = 'https://newsapi.org/v2/top-headlines?' +
          'category=sports&' +
          'q=raptors&' +
          'apiKey=xxxxxxxxxxxxxxxxxxxxxxxxxx';
var req = new Request(url);
fetch(req)
    .then(function(response) {
        raps = response.json();
        return raps;
    });


 function data () {
     if(raps == undefined) {
         console.log("Data is being parsed")
     } else {
         console.log(raps);
         clearInterval(loadData);
         generateData(raps);
     }
 }

 const loadData = setInterval(data, 1000);

 function generateData(raps) {
     let newData = raps.articles;
     console.log(newData);
 }

/////////////////END OF SAMPLE CODE

What I'm getting back is:


Promise {<resolved>: {…}}
__proto__: Promise
[[PromiseStatus]]: "resolved"
[[PromiseValue]]: Object
articles: (20) [{…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}]
status: "ok"
totalResults: 26

我正在尝试访问articles数组。

Answer 1

这应该有效...

let raps;

var url = 'https://newsapi.org/v2/top-headlines?' +
      'category=sports&' +
      'q=raptors&' +
      'apiKey=xxxxxxxxxxxxxxxxxxxxxxxxxx';
var req = new Request(url);
fetch(req)
 .then(response => response.json())
 .then((data) => {
   raps = data;
 });


function data () {
   if(raps == undefined) {
      console.log("Data is being parsed")
   } else {
      console.log(raps);
      clearInterval(loadData);
      generateData(raps);
   }
}

const loadData = setInterval(data, 1000);

function generateData(raps) {
  let newData = raps.articles;
  console.log(newData);
}

Answer 2

以下内容可一次检索文章。您的想法似乎是每秒轮询服务器，但可以轻松地对其进行调整。我使用了更新的async/await方法，将异步查询视为同步查询，使我更容易阅读和理解，但是如果您仍然可以使用fetch/then/catch再次，应该不难重构。

进一步解释我的代码。

我将整个过程作为异步函数运行，该函数立即被调用，请注意代码包装在(async () => { ...})();块中。
await基本上是指等到resolved。这样您就可以看到我等待提取解决，然后等待响应json解决（这实际上是您的解决方案中缺少的一点）

fetch('https://api.com/values/1')
    .then(response => response.json())
    .then(json => console.log(json));

///////////////////SAMPLE CODE
(async () => {
  const url = 'https://newsapi.org/v2/top-headlines?' +
            'category=sports&' +
            'q=raptors&' +
            'apiKey=xxxxxxxxxxxxxxxxxxxxxx';

  const response = await fetch(url);
  let articles = null;
  if (response.ok) {
    const raps = await response.json();
    articles = raps.articles;
  }

  if (articles) {
    articles.forEach(article => console.log(article));
  } else {
    console.log('No articles');
  }
})();
/////////////////END OF SAMPLE CODE

如何从已解决的Promise JavaScript中提取数据？

2 个答案: