How to sort by two criteria - JavaScript

// another example: Object.keys(register).sort((a, b) => Object.keys(register[b]).length - Object.keys(register[a]).length ||
// a.localeCompare(b));

function solve(array) {
   array.sort((a, b) => {
    if(a.length  > b.length) { // first criteria
        return 1;
    } else if(a.length === b.length) {
        return a.toLowerCase().localeCompare(b.toLowerCase()); // second criteria
    } else {
        return -1;
    }
   })

    return(array.join('\n'));
}

solve(['test',
'Deny',
'omen',
'Default']
)