Javascript Multiple path.exists回调，如何知道返回状态是针对哪个文件的？

用于检查文件是否异步存在的node.js内置库函数仅向回调提供布尔值“exists”。我需要检查是否存在多个似乎有问题的文件。我如何知道响应是针对哪个文件的

回调的执行顺序有保证吗？或者我可以以某种方式向回调提供我没有想到的索引吗？显然，我在这里尝试使用“var k”失败了：/

var path = require('path');
var sys = require('sys');

var paths = new Array();
paths.push('file_0');
paths.push('file_1');
paths.push('file_2');

for (var i = 0; i < paths.length; i++)
{
    var k = i;
    path.exists(paths[i], function(exists) {
        var j = i;
        sys.puts("One of the files has this status: " + exists + " but which one?");
        sys.puts("j is: "+j); 
        sys.puts("k is: "+k);
    });
}

---

不幸的是，Javascript将所有变量声明提升到函数顶部，这既愚蠢又不直观。一些解决方法：

使用“（function（）{my loop code}）（）；”效果很好，谢谢！

$ node test.js
One of the files has this status: false but which one?
j is: 3
k is: 2
One of the files has this status: false but which one?
j is: 3
k is: 2
One of the files has this status: false but which one?
j is: 3
k is: 2