关于json排序问题

最近有人问我，关于json排序的问题；我试写了下，感觉也有点啰嗦，欢迎大家来改正。

function orderJson(j) {
    var arr = new Array;
    for (var i in a) {
        var x = eval("({" + i + ":'" + a[i] + "'})");  
        arr.push(x);
    }
    // [{a:1},{b:6},{c:4}]
    var b = arr.sort(function(x, y) {
        var _x, _y;
        for (i in x) _x = x[i];
        for (i in y) _y = y[i];
        if (_x > _y) return 1;
        if (_x < _y) return -1;
        if (_x == _y) return 0;
    }), obj = {}, extend = function(destination, source) {
        for (var property in source) destination[property] = source[property];
        return destination;
    };
    for (var i = 0; i < arr.length; i++) extend(obj, arr[i]);
    return obj;
}

var a = {
    "a": 1,
    "b": 6,
    "c": 4
}; //关于json排序

console.log(orderJson(a));