function ascending( a, b ) {
	if ( a < b ) {
		return -1;
	}
	if ( a > b ) {
		return 1;
	}
	return 0;
}
Returns a comparison result. If `-1`, `a` comes before `b`. If `1`, `b` comes before `a`. If `0`, the order stays the same.

@private
@param {number} a - first number
@param {number} b - second number
@returns {boolean} comparison result