javascript引擎长时间独占线程造成卡顿的解决方案_javascript技巧

function Ansync (totalCount, segmentCount, workCallback, returnCallback)
{
    var num_of_item_for_each_segment = segmentCount;
    var num_of_segment = Math.ceil(totalCount / num_of_item_for_each_segment);
    var count_of_segment = 0;
    var timer;
    var start, end;
    this.process = function(scope, timeout)
    {
        if (scope != undefined)
        {
            workCallback = workCallback.bind(scope);
            returnCallback = returnCallback ? returnCallback.bind(scope) : undefined;
        }
        if (count_of_segment == num_of_segment)
        {
            clearTimeout(timer);
            if (returnCallback != undefined)
                returnCallback();
        }
        else
        {
            start = count_of_segment * num_of_item_for_each_segment;
            end = Math.min(totalCount, (count_of_segment + 1) * num_of_item_for_each_segment);
            if (num_of_segment == 1)//needn't create timer
            {
                workCallback(start, end);
                count_of_segment = 1;
                this.process();
            }
            else
            {
                timer = setTimeout(function ansyncTimeout(){
                    if (workCallback(start, end)) //finish process if function returns true
                    {
                        count_of_segment = num_of_segment;
                    }
                    else
                    {
                        count_of_segment++;
                    }
                    this.scope.process();
                }.bind({scope: this}),timeout == undefined ? Ansync.TimeOut : timeout);
            }
        }
    }
}
Ansync.TimeOut = 5;