如何在node.js中使用Promise.all和Request？ [英] How to use Promise.all with Request in node.js?

问题描述

我想做的事情如下：

Promise.all([
    fetch(url1).then(function(response){ return response.json() }),
        fetch(url2).then(function(response){ return response.json() }),
            fetch(url3).then(function(response){ return response.json() }),
                fetch(url4).then(function(response){ return response.json() })
    ]).then(allResponses => {

    var data1 = allResponses[0];
    var data2 = allResponses[1];
    var data3 = allResponses[2];
    var data4 = allResponses[3];

    // process data....

    });

上面是React.js代码，我想用Node做同样的事情。服务器上的js。问题是我没有提取，我有请求（我应该使用Request吗？）。 https://github.com/request/request
它以这种方式使用.. 。

The above is React.js code, I'd like to do the same thing but with Node.js on the server. Problem is I don't have fetch, I have request (should I even be using Request?). https://github.com/request/request It's used in this way...

var request = require('request');

request(url1, function (error, response, body) {
});

但我如何使用Promise.all请求？因为我想获取多个东西并且只在Node完成所有操作时处理它们，而我宁愿不使用一堆回调。

But how would I use request with Promise.all? Because I want to fetch multiple things and only process them when all are done but in Node, and I'd rather not use a bunch of callbacks.

推荐答案

更简洁地说，在安装node-fetch之后，你可以做一个声明返回的fetch解析为json ...

More concisely, after installing node-fetch, you can make a promise-returning fetch that resolves to json...

const fetch = require('node-fetch');
function fetchJSON(url) {
    return fetch(url).then(response => response.json());
}

...从一系列网址构建一系列承诺...

...build an array of promises from an array of urls...

let urls = [url1, url2, url3, url4];
let promises = urls.map(url => fetchJSON(url));

...当这些承诺解决时做点什么......

...do something when those promises resolve...

Promise.all(promises).then(responses => console.log(responses));

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