在Javascript中类样式对象的实例之后运行回调

我正在接受其他人的代码，不确定我是否正在以正确的方式进行操作

有一个跟踪器“类”（基本上只是一个函数对象，包括一个“初始值设定项”）

该类将调用第三方库

返回结果后应进行回调

以下是我想做的：

var tracker = Tracking.initialize({
        prod: 'OurProduct',
        requiredLayoutKeys: ["scr"],
        requiredInteractiveKeys: ["name", "action"],
        maxQueueSize: 5,
        timeToSend: 5000,
    });

// this code should happen in the callback once tracker is initialized:
InitSessionInfo(
    {sid: tracker.__sid, product: tracker.prod},
    function (returnObj) {
        setSessionIP(tracker.getIP(),function(returnObj){
            OurApp.auth(function (user) {
                OurApp.initialize(user);
            });
        });
    });

以下是跟踪对象在单独文件中的外观：

var Tracking = {
  __required_layout_keys: null,
  __required_interactive_keys: null,
  __maxQueueSize: null,
  __timeToSend: null,
  __initialized: false,

  initialize: function(config){
    Tracking.__initialized = true;
    Tracking.__required_interactive_keys = config.requiredInteractiveKeys;
    Tracking.__required_layout_keys = config.requiredLayoutKeys;
    Tracking.__maxQueueSize = config.maxQueueSize;
    Tracking.__timeToSend = config.timeToSend;
    Tracking.__bid = '';
    Tracking.__sid = '';
    Tracking.__ua = '';

    // get user data from FingerPrintJs2. 
    // The callback needs to happen after these results are returned: 
    new Fingerprint2().get(function(result, components){
        var ua = components.find(function(item){
            return item.key === "user_agent";
        });
        Tracking.__bid = result;
        Tracking.__sid = result + "." + Date.now();
        Tracking.__ua = ua.value;
    });
  },
 // there are other functions here that return ip, etc.
}

不幸的是，“跟踪器”总是以未定义的形式返回

更新：

在此处粘贴调试器时：

var tracker = Tracking.initialize({
    prod: 'OurProduct',
    requiredLayoutKeys: ["scr"],
    requiredInteractiveKeys: ["name", "action"],
    maxQueueSize: 5,
    timeToSend: 5000,
});

debugger;

tracker的值为“未定义”，并且Tracking的值尚未设置其“sid”值

跟踪中的更新：

var Tracking = {
 ...
 initialize: function(){
 ...
 return new Fingerprint2().get(function(result, components){
        var ua = components.find(function(item){
            return item.key === "user_agent";
        });
        Tracking.__bid = result;
        Tracking.__sid = result + "." + Date.now();
        Tracking.__ua = ua.value;
        return Tracking;
    });


 }

---

因此，

fingerprintjs2

返回一个

setTimeout

，这本质上是异步的，但不幸的是，默认情况下无法链接。通过查看

setTimeout

中的代码，您可以看到它正在调用超时完成时传递给

get（）

函数的函数，因此您可以通过承诺来确保事情在应该发生的时候发生

您需要做的是将

new Fingerprint2（）.get（）

调用包装为一个承诺，然后在传递到

get

函数的“

done

”函数（在setTimeout内调用的函数）中解析该承诺

然后，您可以从

跟踪

对象中的

初始化

函数返回承诺，以便在成功初始化/更新数据后将其链接并执行操作

使用Promise对象的ES6版本

var Tracking = {
  __required_layout_keys: null,
  __required_interactive_keys: null,
  __maxQueueSize: null,
  __timeToSend: null,
  __initialized: false,
  initialize: function(config){
    Tracking.__initialized = true;
    Tracking.__required_interactive_keys = config.requiredInteractiveKeys;
    Tracking.__required_layout_keys = config.requiredLayoutKeys;
    Tracking.__maxQueueSize = config.maxQueueSize;
    Tracking.__timeToSend = config.timeToSend;
    Tracking.__bid = '';
    Tracking.__sid = '';
    Tracking.__ua = '';
    // get user data from FingerPrintJs2. 
    // The callback needs to happen after these results are returned: 
    // return the promise so we can chain
    return new Promise(function (resolve, reject) {
        new Fingerprint2().get(function(result, components){
          var ua = components.find(function(item){
            return item.key === "user_agent";
          });
          Tracking.__bid = result;
          Tracking.__sid = result + "." + Date.now();
          Tracking.__ua = ua.value;
          resolve(Tracking); // resolve promise with updated Tracking obj
        });
    });
  },
  // there are other functions here that return ip, etc.
};

var tracker = null;
Tracking.initialize({
  prod: 'OurProduct',
  requiredLayoutKeys: ["scr"],
  requiredInteractiveKeys: ["name", "action"],
  maxQueueSize: 5,
  timeToSend: 5000,
}).then(function (updatedTracker) {
    tracker = updatedTracker;
    console.log(tracker);
});

使用$.Deferred（）的ES5兼容版本

这里的语法有一点变化，但并没有什么剧烈的变化——而且想法是完全一样的

var Tracking = {
  __required_layout_keys: null,
  __required_interactive_keys: null,
  __maxQueueSize: null,
  __timeToSend: null,
  __initialized: false,
  initialize: function(config){
    Tracking.__initialized = true;
    Tracking.__required_interactive_keys = config.requiredInteractiveKeys;
    Tracking.__required_layout_keys = config.requiredLayoutKeys;
    Tracking.__maxQueueSize = config.maxQueueSize;
    Tracking.__timeToSend = config.timeToSend;
    Tracking.__bid = '';
    Tracking.__sid = '';
    Tracking.__ua = '';
    // get user data from FingerPrintJs2. 
    // The callback needs to happen after these results are returned: 
    var deferred = $.Deferred(); // create deferred object
    new Fingerprint2().get(function(result, components){
          var ua = components.find(function(item){
            return item.key === "user_agent";
          });
          Tracking.__bid = result;
          Tracking.__sid = result + "." + Date.now();
          Tracking.__ua = ua.value;
          deferred.resolve(Tracking); // resolve deferred object with updated Tracking obj
        });
    return deferred.promise(); // return deferred promise that we can chain off of
  },
  // there are other functions here that return ip, etc.
};

var tracker = null;
// jQuery deferreds work with $.when(promise).then() syntax
$.when(Tracking.initialize({
  prod: 'OurProduct',
  requiredLayoutKeys: ["scr"],
  requiredInteractiveKeys: ["name", "action"],
  maxQueueSize: 5,
  timeToSend: 5000,
})).then(function (updatedTracker) {
    tracker = updatedTracker;
    console.log(tracker);
});

---

您好@mhodges，在设置您的更改后，我收到一个错误

无法读取
}上未定义的
的属性'then'。然后（函数（updateTracker）

line.@donaldduck好的，给我几分钟试着调试一下，我会告诉你我做了什么find@donaldduckOhhh好的，我只是看了指纹的代码。我知道他们在做什么。这实际上不是异步的-乍一看就是这样。他们的get函数是这样的：

get:function（done）{…return done（arg1，arg2）}

。这意味着您只需从get函数回调返回

跟踪

，您应该是golden。我将更新我的帖子accordingly@donaldduck更新。看一看。非常感谢您的全面指导。ES6版本非常适合我，工作非常完美。