Javascript在实例化后订阅回调函数

javascript subscribe to callback function after instanciation

本文关键字：回调 函数 实例化 Javascript      更新时间：2023-09-26

我有一个这样的Javascript对象:

function App(callback){
// Call some "long running functions meant for initialization
callback(this);
}

在我的主模板页面(_Layout。我像这样实例化它:

_Layout.cshtml 

var oApp = new App(function(initializedApp){
    // Instanciate here other Javascript components that depend on 
    // App initialization
    var oComponent1 = new Component1(initializedApp);
});

这个工作很好!当应用程序完成初始化并且一切正常时，才初始化Component1。

Page1出现问题。cshtml(在_Layout中呈现)。cshtml并可以访问oApp)。Page1还必须初始化自己的组件，这些组件需要App完全初始化。

Page1.cshtml 

// How do I "subscribe to the App callback function so that Compnent2, s
// specific to the Page1.cstml, is initialized afetr App has finished
// its initialization ???
var oComponent2 = new Compnent2(oApp);
oApp.callback(); // ???
oApp(function(initializedApp){ // code here... });  //???

感谢

洛伦佐

你的跑步模式很有趣。我建议使用一种更低调的方式来初始化和调用javascript。我想说，CSHTML中的大多数JS调用都可以被认为是代码气味。

不管怎样，我会回答你的问题。我将更改App以具有注册回调的能力: 
function App(callbacks)
{
    var self = this;
    self.callbacks = [];
    self.addCallbacks = function(newCallbacks)
    {
        //allow either a single callback or an array of callbacks
        if(isFunction(callbacks)
        {
            self.callbacks.push(newCallbacks); //single callback
        }
        else
        {
            for(var i = 0; i < newCallbacks.length; i++)
            {
                //theoretically, you can have multi-dimensional arrays of callbacks, but that's just excessive
                self.addCallbacks(newCallbacks[i]);
            }
        }
    };
    self.addCallbacks(callbacks);
    //some point later, call all the callbacks:
    for(var i = 0; i < self.callbacks.length; i++)
    {
        self.callbacks[i](this);
    }
}

然后，在你的Page1.cshtml中:

var oComponent2 = new Compnent2(oApp);
var mycallback = function(initializedApp){ // code here... };
oApp.addCallbacks(mycallback);
//or, if you have many callbacks to register:
var mycallbacks = [
    function(initializedApp){ // code here... },
    function(initializedApp){ // code here... }
];
oApp.addCallbacks(mycallbacks);

isFunction借来从这里:

var isFunction = function(functionToCheck) 
{
    var getType = {};
    return functionToCheck && getType.toString.call(functionToCheck) === '[object   Function]';
}
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