/**
     * Sort arrays alphabetically, according to the string returned by fn.
     * Elements for which fn returns null or undefined are sorted to the end in an undefined order.
     *
     * @param array to sort
     * @param fn to get a string to sort by
     * @returns sorted array
     */
    export function sortedAlphabetically<T>(array: T[], fn: (arg: T) => string): T[] {
        return array.sort(alphabetically(fn));
    }

    /**
     * Creates a comparator that sorts items alphabetically by a string key returned from `fn`.
     *
     * The comparator places falsy keys (null, undefined or empty string) after non-falsy keys;
     * two falsy keys compare as equal.
     * 
     * @param fn to get a string to sort by
     * @returns A comparator `(a, b) => number` suitable for `Array.sort`.
     */
    export function alphabetically<T>(fn: (arg: T) => string): (a: T, b: T) => number {
        return (a: T, b: T) => {
            const aVal = fn(a);
            const bVal = fn(b);
            if (!aVal) {
                return !bVal ? 0 : 1;
            } else if (!bVal) {
                return -1;
            }
            return aVal.localeCompare(bVal, undefined, { sensitivity: "accent" });
        }
    }

.sort(ArrayUtils.alphabetically(a => a.alias));