How to order a JSON object by two keys?

Question

I have a JSON object that I want to sort by one key first, then by a second key similar to ordering by two columns in SQL. Here is a sample of the JSON I would have:

{
   "GROUPID":3169675,
   "LASTNAME":"Chantry"
}

I would like to order all the results by the GROUPID and then by LASTNAME. I've used the JSON sort function to sort by one key but not multiple.

Any help would be great.

Answer 1

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.