Sort an array of objects by property

objectSort.js

var objectSort = function(array,sortKey,sortFunction) {
    switch (sortFunction) {
        case "number-asc":
            return array.sort(function(a, b){
                return a[sortKey]-b[sortKey];
            });
            break;
        case "number-desc":
            return array.sort(function(a, b){
                return b[sortKey]-a[sortKey];
            });
            break;
        case "alpha-desc":
            return array.sort(function(a,b){
                if(a[sortKey].toLowerCase() < b[sortKey].toLowerCase()) return 1;
                if(a[sortKey].toLowerCase() > b[sortKey].toLowerCase()) return -1;
                return 0;
            });
            break;
        default:
            return array.sort(function(a,b){
                if(a[sortKey].toLowerCase() < b[sortKey].toLowerCase()) return -1;
                if(a[sortKey].toLowerCase() > b[sortKey].toLowerCase()) return 1;
                return 0;
            });
            break;
    }
}
// objectSort([{waffles:1,derp:"apple"},{waffles:3,derp:"cat"},{waffles:2,derp:"banana"}],"waffles","alpha-desc")
// > [{waffles:3,derp:"cat"},{waffles:2,derp:"banana"},waffles:1,derp:"apple"}]