Question

非常简单的Node.js（控制台应用）代码：

var request = require("request");
var q = require("q");
var data = new Object();
var deferred = new q.defer();

var url1 = "https://www.google.com"
var url2 = "https://www.yahoo.com"
process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";

console.log('begin data1');
requestData(url1) //Promises seem to be working fine here
    .then(function () { console.log('finished data1'); }) //At this point, we go back to async, and everything from here down executes at the same time.
    .then(function () { console.log('begin data2'); })
    .then(function () { requestData(url2); }) //Expected behavior is that it should pause here, and execute everything below after the request is complete.
    .then(function () { console.log('finished data2'); })
    .then(function () { console.log(data); })
    .then(function () { console.log('finished write2'); })
    .then(function () { console.log('operation completed!'); });

function requestData(url) {
    console.log(url);
    data = new Object();
    console.log(data);
    deferred = new q.defer();
    console.log(deferred);
    request({
        url: url,
        json: true
    }, function (error, response, obj) {
        if (!error && response.statusCode === 200) {
            data = obj;
            deferred.resolve();
            console.log(deferred);
        } else {
            console.log('err');
        }
    });  
   return deferred.promise;
}

问题出在第一个.then语句之后，所有内容都是异步执行的。我希望第二次运行'requestData'调用与第一次调用同步。

请原谅我的控制台日志以进行调试。

我在这里做错了什么？

Answer 1

问题是你没有在value方法中返回一个承诺。

试试这个：

then

Chain Promises Node.js使用Q Not Working

1 个答案: