我会用可怕的看起来,手拍的漫画来回答,第二张图像是为什么结果在您的代码示例中无法定义的原因。

此分類上一篇

urls = ['https://jsonplaceholder.typicode.com/todos/2',
        'https://jsonplaceholder.typicode.com/todos/3']

{"userId":1,"id":2,"title":"quis ut nam facilis et officia qui",
 "completed":false}
{"userId":1,"id":3,"title":"fugiat veniam minus","completed":false}

namesonly = ['two', 'three']

[{"name":"two","loremipsum":"quis ut nam facilis et officia qui"},
{"name":"three","loremipsum":"fugiat veniam minus"}]

...
  "release-groups": [
    {
      "id": "1dc4c347-a1db-32aa-b14f-bc9cc507b843",
      "secondary-type-ids": [],
      "first-release-date": "2000-07-10",
      "primary-type-id": "f529b476-6e62-324f-b0aa-1f3e33d313fc",
      "disambiguation": "",
      "secondary-types": [],
      "title": "Parachutes",
      "primary-type": "Album"
    },
...

此 JSON 剪辑显示 Coldplay 的第一张专辑是 Parachutes. 它还提供了一个 ID,在这种情况下 1dc4c347-a1db-32aa-b14f-bc9cc507b843,这是专辑的独特标识。

对于每个专辑,JSON答案包含一些图像,其中一个是专辑的前面覆盖。

{
  "images": [
    {
      "approved": true,
      "back": false,
      "comment": "",
      "edit": 22132705,
      "front": true,
      "id": 4086974851,
      "image": "http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851.jpg",
      "thumbnails": {
        "250": "http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851-250.jpg",
        "500": "http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851-500.jpg",
        "1200": "http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851-1200.jpg",
        "large": "http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851-500.jpg",
= = >   "small": "http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851-250.jpg"
    },
...

这里有兴趣的是“小”的线:“http://coverartarchive.org/release/435fc965-9121-461e-b8da-d9b505c9dc9b/4086974851-250.jpg”。

创建和视觉化Mashup的代码

const lock = setTimeout(() => {}, 43210);
const albumsArray = [];
const urlsArray = [];
const urlOuter = 'https://musicbrainz.org/ws/2/artist/' +
  pm.collectionVariables.get('MBID') + '?fmt=json&inc=url-rels+release-groups';
pm.sendRequest(urlOuter, (_, responseO) => {
  const bandName = responseO.json().name;
  const albums = responseO.json()['release-groups'];
  for (const item of albums) {
    albumsArray.push(item.title);
    urlsArray.push('https://coverartarchive.org/release-group/' + item.id);
  }
  albumsArray.length = urlsArray.length = 15;
  const images = [];
  let countDown = urlsArray.length;
  urlsArray.forEach((url, index) => {
    asynchronousCall(url, imageURL => {
      images[index] = imageURL;
      if (--countDown === 0) { // Callback for ALL starts on next line.
        clearTimeout(lock); // Unlock the timeout.
        const albumTitles = albumsArray.map(value => ({ title: value }));
        const albumImages = images.map(value => ({ image: value }));
        const albumsAndImages = albumTitles.map(
          (item, i) => Object.assign({}, item, albumImages[i]));
        const template = `<table>
          <tr><th>` + bandName + `</th></tr>
          {{#each responseI}}
          <tr><td>{{title}}<br><img src="{{image}}"></td></tr>
          {{/each}}
        </table>`;
        pm.visualizer.set(template, { responseI: albumsAndImages });
      }
    });
  });
  function asynchronousCall (url, callback) {
    pm.sendRequest(url, (_, responseI) => {
      callback(responseI.json().images.find(obj => obj.front === true)
        .thumbnails.small); // Individual callback.
    });
  }
});

结果和文档

此分類上一篇

---

下面我写的例子表明如何

处理无同步的 HTTP 通话; 等待每个 API 通话的响应; 使用 Promise 模式; 使用 Promise.all 模式加入多个 HTTP 通话;

[
 "search?type=playlist&q=%22doom%20metal%22",
 "search?type=playlist&q=Adele"
]

对于每个项目,一个新的承诺将燃烧一个区块 - ExecutionBlock,打破结果,根据结果序列安排一个新的承诺集,这是 Spotify 用户对象的列表,并在 ExecutionProfileBlock 中无同步执行新的 HTTP 通话。

然后,你可以看到一个被遗弃的承诺结构,允许你扫描多个和完全无同步的遗弃的HTTP通话,并通过 Promise.all 加入每个子组的通话的结果。

-H "Authorization: Bearer {your access token}" 

我在这里讨论了这个解决方案。

简单的代码例子将 XHR 在 Node.js 转换为 async-await

var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
var xhttp = new XMLHttpRequest();

function xhrWrapWithPromise() {
  return new Promise((resolve, reject) => {
    xhttp.onreadystatechange = function() {
      if (this.readyState == 4) {
        if (this.status == 200) {
          resolve(this.responseText);
        } else {
          reject(new Error("Couldn't feth data finally"));
        }
      }
    };
    xhttp.open("GET", "https://www.w3schools.com/xml/xmlhttp_info.txt", true);
    xhttp.send();
  });
}

// We need to wrap await in Async function so and anonymous IIFE here
(async _ => {
  try {
    let result = await xhrWrapWithPromise();
    console.log(result);
  } catch (error) {
    console.log(error);
  }
})();

下面是一個工作的例子: const validateName = async userName => { const url = "https://jsonplaceholder.typicode.com/todos/1"; try { const response = await axios.get(url); return response.data } catch (err) { return false; } }; validateName("user").then(data => console.log(data)).catch(reason => console.log(reason.message)).as-console-wrapper { max-height: 100%!im

ECMAScript 6 有“发明器”,允许您轻松地在无同步的风格编程。

function* myGenerator() {
    const callback = yield;
    let [response] = yield $.ajax("https://stackoverflow.com", {complete: callback});
    console.log("response is:", response);

    // examples of other things you can do
    yield setTimeout(callback, 1000);
    console.log("it delayed for 1000ms");
    while (response.statusText === "error") {
        [response] = yield* anotherGenerator();
    }
}

要运行上面的代码,你会这样做:

const gen = myGenerator(); // Create generator
gen.next(); // Start it
gen.next((...args) => gen.next([...args])); // Set its callback function

如果您需要针对不支持 ES6 的浏览器,您可以通过 Babel 或关闭编译器运行代码,以创建 ECMAScript 5。

呼叫回归器被包围在一个序列,并在你阅读它们时被破坏,以便模式可以处理有多个论点的呼叫回归器。

const [err, data] = yield fs.readFile(filePath, "utf-8", callback);