Sorting an array of nested objects

sort-nested-objects.js

var arr = [
    {details: {name: {first: 'Joseph', last: 'Chapman'}}},
    {details: {name: {first: 'Andrew', last: 'Chapman'}}},
    {details: {name: {first: '234', last: '111'}}},
    {details: {name: {first: 'Joseph', last: 'Hinge'}}},
    {details: {name: {first: 'Simon', last: 'Andrews'}}},
    {details: {name: {first: 'Robert', last: 'Hinge'}}}
];
    
var sortBy = function (key, minor) {
    var compare = function (a, b, o, p) {
         if (a === b) {
                return typeof minor === 'function' ? minor(o, p) : 0;
            }
            if (typeof a === typeof b) {
                return a < b ? -1 : 1;
            }
            return typeof a < typeof b ? -1 : 1;        
    }
    return function (o, p) {
        var a, b, keys, tmp, i, l, n = 0;
        if (o && p && typeof o === 'object' && typeof p === 'object') {
            keys = key.split(' ');
            if (keys.length > 1) {
                i = keys.length-1;
                while (n++ < i) {
                    tmp = keys[n];
                    for (l in o) {
                        if (o.hasOwnProperty(l) && typeof o[l][tmp] !== 'undefined') {
                            if (typeof o[l][tmp][keys[i]] !== 'object') {
                                a = o[l][tmp][keys[i]];
                                b = p[l][tmp][keys[i]];
                                break;
                            } else {
                                continue;
                            }    
                        }
                    }
                    
                }
            } else {
                a = o[key];
                b = p[key];   
            }
            return compare(a, b, o, p);
        }
    }
};

arr.sort(sortBy('details name last', sortBy('details name first')));

// arr is [
// {first: '234', last: '111'},
// {first: 'Simon', last: 'Andrews'},
// {first: 'Andrew', last: 'Chapman'},
// {first: 'Joseph', last: 'Chapman'},
// {first: 'Joseph', last: 'Hinge'},
// {first: 'Robert', last: 'Hinge'}]