total-order/lex

/**
 * Generates a binary lexicographical comparator for fixed size arrays.
 *
 * https://en.wikipedia.org/wiki/Lexicographical_order
 *
 * compare( a , b ) should always return
 *   - a negative value if a < b
 *   - a positive value if a > b
 *   - zero if a === b
 *
 */

export default function fixedlexicographical(compare, length) {
    /**
     * Compares 2 fixed size arrays a and b of size len lexicographically.
     */

    return function (a, b) {
        for (let i = 0; i < length; ++i) {
            const d = compare(a[i], b[i]);

            if (d !== 0) return d;
        }

        return 0;
    };
}