避免“无响应的脚本”在foreach循环中的消息 [英] Avoiding "Unresponsive Script" message in a foreach loop

问题描述

  for（object in property ）{
 difficultTask（）; 
 
 $ / code> 

我已经看到你可以用 setTimeout 这可以让你周期性地将控制权交还给浏览器;然而，我还没有看到任何能够做到这一点与foreach循环，只有一个索引for循环。此外，这些任务不能异步完成，因为每次迭代都依赖于前一次迭代的结果。

我能想到的一个解决方案是将我的对象分成很多更小的对象，遍历其中的每一个，设置每个之间的超时，但我想看看是否有可能，而不诉诸于此。

是有一种方法可以做到这一点，而不会彻底改变我有我的对象？

解决方案

获取所有的属性到一个数组，然后你可以循环访问一个索引变量和 setTimeout（）：

  var props = []; 
 for（property in object）{
 props.push（property）; 
} 
 
 var index = 0; 
函数nextChunk（）{
 if（index< props.length）{
 \\ hardTask（object [props [index ++]]））; 
 
 //在我们让浏览器处理事件之后安排下一块工作
 setTimeout（nextChunk，1）; 
} 
 
} 
 nextChunk（）; 
  

您也可以将所有道具放到一个数组中，这是您不需要IE7或IE8兼容性：

  var props = Object.keys（object）; 
  

---

根据长时间运行的任务的不同，web工作人员也可能是一个有趣的选择，但在IE 10之前不支持IE。

I am writing a javascript program with a very long-running foreach loop like the following:

for (property in object) {
    difficultTask();
}

I've seen that you can do some things with setTimeout which can allow you to periodically return control to the browser; however, I haven't seen any that are able to do this with a foreach loop, only a for loop with an index. Additionally, these tasks cannot be completed asynchronously since each iteration depends on a result from the previous iteration.

One solution I can think of is to split up my object into a lot of smaller objects and iterate through each of them, setting a timeout in between each one, but I'd like to see if this is possible without resorting to that.

Is there a way to do this without drastically changing how I have my objects?

解决方案

Get all the properties into an array and then you can cycle through the array with an index variable and a setTimeout():

var props = [];
for (property in object) {
    props.push(property);
}

var index = 0;
function nextChunk() {
    if (index < props.length) {
        difficultTask(object[props[index++]]));

        // schedule the next chunk of work after we let the browser process events
        setTimeout(nextChunk, 1);
    }

}
nextChunk();

You could also get all the props into an array with this is you don't need IE7 or IE8 compatibility:

var props = Object.keys(object);

---

Depending upon what the long running task does, web workers could also be an interesting option, but no support in IE until IE 10.

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