javascript - Typescript + Jquery Ajax + 这个

Question

我正在将一些 javascript 代码移植到 typescript，但遇到了一个问题。

我有一个将对象作为上下文传递的 ajax 调用，该对象包含一些回调和一些其他信息，这些信息由成功或错误回调读出，指示成功调用应重定向到的位置:

function SomeAjaxService
{
    var self = this;

    self.CheckErrorType = function(...) {
        // Do something
    };

    var SuccessProxyCallback = function(results) {
        // Do some stuff with results, like send off some events
        this.successCallback(results);
    };

    var FailureProxyCallback = function(...) {
        // Do some stuff with errors, and fire some events
        var someErrorType = self.CheckErrorType(...);
        this.failureCallback(someErrorType);        
    };

    self.SendRequest = function(requestArgs) {
        var ajaxSettings = {
            context: requestArgs,
            // Assign a load of stuff
        };

        $.ajax(ajaxSettings);
    };
}

现在您可以看到失败代理调用本地方法以及使用“this”上下文对象。那么如何使用 typescript 处理这种情况呢？

你能不能只在构造函数中设置 self = this 然后像以前一样继续？

== 编辑 ==

这里要求的是上面的类表示，显示了由于缺少 self 变量而需要 2 件事的问题。

class SomeAjaxService
{
    public CheckErrorType(someArg1: any, someArg2: any) {
        // Do some stuff with data
    };

    private SuccessProxyCallback(results: any) {
        // Do some stuff with results, like send off some events
        this.successCallback(results); 

        // Does the above *THIS* usage point to the context of the 
        // Ajax call or the actual instantiated class
    };

    private FailureProxyCallback(...) {
        // Do some stuff with errors, and fire some events
        var someErrorType = this.CheckErrorType(...);

        // The above *THIS* call cannot be correct if the context has overwritten
        // the scope of this, however I dont know if this is true, do I even need
        // this.CheckErrorType to invoke a local method?

        this.failureCallback(someErrorType);        

        // As mentioned above same issue here but the *THIS* should hopefully
        // point to the context object on the ajax object not the local instance.
    };

    public SendRequest(requestArgs: any) {
        var ajaxSettings : JqueryAjaxSettings = {
            context: requestArgs,
            // Assign a load of stuff
        };

        $.ajax(ajaxSettings);
    };
}

正如我在上面所说的，主要问题是在一个方法中我需要调用一个实例方法以及从 ajax 调用中调用上下文对象上的一个方法。使用原始 javascript 我将有 self = this 然后我可以绕过 this 被覆盖，这是将 ajax 异步状态对象保持在范围内所必需的。

Answer 1

Can you just set self = this in the constructor and continue as you were before?

抽象地说，在构造函数中执行此操作通常不会解决任何问题(除非您稍后在该方法中捕获它——见下文)。 TypeScript 类将类实例数据存储在对象本身上，而不是捕获局部变量。因为 self 将存储在 this 对象中，所以您最终不会拥有以前没有的任何东西。

这是一种方法:

class SomeAjaxService
{
    private FailureProxyCallback(context, arg) {
        // now 'this' is the class instance and 'context' is requestArgs 
    }

    public SendRequest(requestArgs) {
        var self = this; // Note: captured local used in closure below
        var ajaxSettings = {
            context: requestArgs,
            // Do not use an arrow function here, even though it's tempting!
            error: function(arg) { self.FailureProxyCallback(this, arg) }
        };

        $.ajax(ajaxSettings);
    };
}