Sort array with undefined object

Question

Stuck with one problem. I have to sort my array of objects by some values. For example by department name -> department.name. But sometimes department will have no any keys department: undefined. So when i will use department.name i will get errors.

Questions is: Is it possible to sort array with this criteria? And how to modify my function to do it right way?

Thanks!

My function

sort(type) {
    const isSorted = this.state.sorted[type];
            let direction = isSorted ? 1 : -1;
            const sorted = [].slice.call(employees).sort((a, b) => {
                if (a.department[type] === b.department[type]) { return 0; }
                    return a.department[type] > b.department[type] ? direction : direction * -1;
            }
}