递归'setTimeout'函数调用最终会杀死JS引擎吗？ [英] Will a recursive 'setTimeout' function call eventually kill the JS Engine?

问题描述

假设我每隔10秒就需要从服务器获取一些数据。我有一个函数通过AJAX获取数据，然后调用setTimeout再次调用此函数：

Let's say I have some data that I need to get from the server about every 10 seconds. I would have a function that gets the data via AJAX and then call setTimeout to call this function again:

function GetData(){
   $.ajax({
       url: "data.json",
       dataType: "json",
       success: function(data){
         // do somthing with the data

         setTimeout(GetData, 10000);
      },
      error: function(){
         setTimeout(GetData, 10000);
      }
   });
}

如果有人让网页全天开放，可能会有数千个递归函数调用。

If someone leaves the web page open all day, it could get thousands of recursive function calls.

我不想使用setInterval，因为它没有考虑网络延迟。如果网络繁忙且处理请求需要15秒，我不想在获得AJAX超时之前再次询问它。

I don't want to use setInterval because that does not take into account network delay. If the network is busy and it takes 15 seconds to process the request, I don't want to ask it again before I get the AJAX timeout.

什么是最好的处理需要定期调用的函数的方法吗？

What is the best way to handle a function that needs to be called periodically?

推荐答案

没有实际的递归，因为对GetData的调用被延迟了同时销毁JavaScript上下文。所以它不会使JS引擎崩溃。

There's no actual recursion because the call to GetData is delayed and the JavaScript context is destroyed in the meantime. So it won't crash the JS engine.

对于你的代码示例，这基本上是JS引擎级别会发生的事情：

For your code sample, this is basically what will happen at the JS engine level:

1. 初始化JS引擎


2. 创建GetData函数上下文


3. 执行包含setTimeOut的GetData语句


4. setTimeOut指示JS引擎在10秒内调用函数


5. 销毁GetData函数上下文


6. 此时，就内存使用而言，我们又回到了第1步。唯一的区别是JS引擎存储了对函数的引用以及何时调用它（让我们调用这个数据futureCall）。


7. 10秒后，从步骤2开始重复。futureCall将被销毁。

1. Initialize JS engine
2. Create GetData function context
3. Execute GetData statements including "setTimeOut"
4. "setTimeOut" instruct the JS engine to call a function in 10 seconds
5. Destroy GetData function context
6. At this point, in terms of memory use, we are back to step 1. The only difference is that the JS engine stored a reference to a function and when to call it (lets call this data "futureCall").
7. After 10 seconds, repeat from step 2. "futureCall" is destroyed.

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