How to order a JSON object by two keys?

Here is a generic way to sort an array of objects, with multiple columns:

var arr = [
    { id:5, name:"Name3" },
    { id:4, name:"Name1" },
    { id:6, name:"Name2" },
    { id:3, name:"Name2" }
],

// generic comparison function
cmp = function(x, y){
    return x > y ? 1 : x < y ? -1 : 0; 
};

//sort name ascending then id descending
arr.sort(function(a, b){
    //note the minus before -cmp, for descending order
    return cmp( 
        [cmp(a.name, b.name), -cmp(a.id, b.id)], 
        [cmp(b.name, a.name), -cmp(b.id, a.id)]
    );
});

To add other columns to sort on, you can add other items in the array comparison.

arr.sort(function(a, b){
    return cmp( 
        [cmp(a.name, b.name), -cmp(a.id, b.id), cmp(a.other, b.other), ...], 
        [cmp(b.name, a.name), -cmp(b.id, a.id), cmp(b.other, a.other), ...]
    );
});

EDIT: per @PhilipZ comment below, the array comparison in JS convert them in strings separated by comas.

Assuming you have an array of objects:

var data = [
    { "GROUPID":3169675, "LASTNAME":"Chantry" },
    { "GROUPID":3169612, "LASTNAME":"Doe" },
    ...
];

You can use a custom comparator to do the sorting. To sort first by GROUPID, and then by LASTNAME, the logic to compare two objects would be:

if GROUPID of first is smaller than second
    return -1;
else if GROUPID of first is larger than second
    return 1;
else if LASTNAME of first is smaller than second
    return -1;
else if LASTNAME of first is larger than second
    return 1;
else
    return 0;

To sort the object array, use the above algorithm and call the sort method on the array. After sorting is done, data should have the elements in required sorted order.

data.sort(function(a, b) {
    // compare a and b here using the above algorithm
});

Here's another very similar question I answered recently. It's regarding sorting on multiple columns using jQuery, but you can strip out the jQuery part easily. It presents some customizable approaches which can extend to multiple columns.