Question

我正在使用q package将我的js代码从异步转换为同步。我不知道我的理解是否正确。我写了下面的代码段

var Q = require('q')

function onMessage() {
    console.log("Before calling Q.fncall");
    Q.fcall(processMessage)
        .then(function () {
            console.log("processMessage execution compleated");
        })
        .done();
    console.log("Calling Q.fncall Compleated");
    return true;
}

function processMessage() {
    var defer = Q.defer();
    console.log("processMessage Entered");
    setTimeout(function () {
        console.log("processMessage processed");
        defer.resolve();
        console.log("processMessage defer Resolved");
    }, 10)
    console.log("ProcessMessage Before Exit");
    return defer.promise;
}
onMessage()

代码的输出为:::: Before calling Q.fncall Calling Q.fncall Compleated processMessage Entered ProcessMessage Before Exit processMessage processed processMessage defer Resolved processMessage execution compleated

但是我的期望是得到:::: Before calling Q.fncall processMessage Entered ProcessMessage Before Exit processMessage processed processMessage defer Resolved processMessage execution compleated Calling Q.fncall Compleated

有什么我想念的东西吗？怎么能实现？...

Answer 1

这应该解决

var Q = require('q')

function onMessage() {
  console.log("Before calling Q.fncall");
  return new Promise(resolve => {
    Q.fcall(processMessage)
      .then(function () {
        console.log("processMessage execution compleated");
        console.log("Calling Q.fncall Compleated");
      })
      .done(() => resolve(true));
  })
}

function processMessage() {
  var defer = Q.defer();
  console.log("processMessage Entered");
  setTimeout(function () {
    console.log("processMessage processed");
    defer.resolve();
    console.log("processMessage defer Resolved");
  }, 10)
  console.log("ProcessMessage Before Exit");
  return defer.promise;
}

onMessage();

Node.js'q'包异步进行同步

1 个答案: