some obj manipulation and validation functions

JSobj

var objcopy = function(old) {
    if (old === undefined) {
	return undefined;
    }
    if (old === null) {
	return null;
    }

    if (old.parentNode) {
	return old;
    }

    switch (typeof old) {
    case "string" : {
	return old.substring(0);
	break;
    }

    case "number" : {
	return old + 0;
	break;
    }

    case "boolean" : {
	return old === true;
	break;
    }

    }

    var newobj = ($.isArray(old)) ? [] : {};
    $.each(old, function(k, v){
	newobj[k] = objcopy(v)
    });

    return newobj;
}

var objmerge = function(dst, src) {
    dst = dst || {};
    src = src || {};
    
    var merge = objcopy(dst);
    for(var k in src) {
	merge[k] = src[k];
    }

    return merge;
}

var objkeys = function(obj) {
    var keys = [];
    $.each(obj, function(k,v) {
	if (obj.hasOwnProperty(k)) {
	    keys.push(k);
	}
    });

    return keys;
}

var objcmp = function(a, b, strict_ordering) {
    if (!a || !b) {
	return a === b;
    }
    if (typeof a != typeof b) {
	return false;
    }
    if (typeof a != 'object') {
	return a === b;
    } else {
	if ($.isArray(a)) {
	    if (!($.isArray(b))) {
		return false;
	    }
	    if (a.length != b.length) {
		return false;
	    }
	} else {
	    var a_keys = [];
	    for(var k in a) {
		if (a.hasOwnProperty(k)) {
		    a_keys.push(k);
		}
	    }
	    var b_keys = [];
	    for(var k in b) {
		if (b.hasOwnProperty(k)) {
		    b_keys.push(k);
		}
	    }

	    if (!strict_ordering) {
		a_keys.sort();
		b_keys.sort();
	    }

	    if (a_keys.join(',') !== b_keys.join(',')) {
		return false;
	    }
	}

	var same = true;
	$.each(a, function(k) {
	    var diff = objcmp(a[k], b[k]);
	    same = same && diff;
	    if (!same) {
		return false;
	    }
	});

	return same;
    }
}

var uniq = function(arr) {
    var len = arr.length;
    var set = {};

    for(var i=0; i<len; i++) {
	set[arr[i]] = true;
    }
    
    return objkeys(set);
}