Question

我想将JavaScript中使用的for循环转换为异步格式，以便在浏览器中运行时删除不响应错误的脚本。我的代码如下：

links.Timeline.prototype.stackItemsCheckOverlap = function(items, itemIndex,
    itemStart, itemEnd) {

    var eventMargin = this.options.eventMargin, 
          collision = this.collision;

    var item1 = items[itemIndex];

    //for loop that I want to change as asynchronous
    for (var i = itemEnd; i >= itemStart; i--) {

        var item2 = items[i];
        if (collision(item1, item2, eventMargin)) {
            if (i != itemIndex) {
            return item2;
        }
    }
}

Answer 1

您可以使用计时器，以便内部延迟执行。这是一个例子：

function asyncLoop(array, callback){
  var i = 0;
  var timer = setInterval(function(){
    callback.call(array, array[i]);
    if(++i === array.length) clearInterval(timer);
  }, 0);
}

asyncLoop([1,2,3], function(item){
  // this will run per item but will not block execution
});

Answer 2

可能重复：JavaScript and Threads

您可能希望将工作人员用于后台任务。

了解详情：http://www.w3schools.com/html/html5_webworkers.asp

以下是与您的案例相关的示例：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
    </head>
    <body>
        <script id="worker1" type="javascript/worker">
            self.onmessage = function(e) {
                // Whatever you want to run in background, for example
                for (var i = 0; i < 100; i++) {
                    console.log(i);
                }
                self.postMessage(0); // Post back a message, to close the worker
            }
        </script>

        <script>
            function run_task() {
                if (typeof(Worker) != "undefined") {
                    // Here I am using a blob so I can run worker without using a separate file. It works on Chrome, but may not work on other browsers
                    var blob = new Blob([document.querySelector('#worker1').textContent], { type: "text/javascript" });
                    var worker = new Worker(window.URL.createObjectURL(blob));
                    worker.onmessage = function(e) {
                        worker.terminate(); // Close the worker when receiving the postback message
                    }
                    worker.postMessage(1); // Start the worker. You can also use this function to pass arguments to the worker script.
                } else {
                    // You browser does not support Worker
                }
            }
            run_task(); // Run the function. You probably want to trigger this somewhere else
        </script>
    </body>
</html>

参考文献：https://stackoverflow.com/a/6454685/2050220

如何将java脚本中的for循环转换为异步

2 个答案: