code: function getRelativeDirection(direction, referenceDirection) {
    verifyAbsoluteDirection(direction);
    verifyAbsoluteDirection(referenceDirection);
  
    const index =
      (ABSOLUTE_DIRECTIONS.indexOf(direction) -
        ABSOLUTE_DIRECTIONS.indexOf(referenceDirection) +
        RELATIVE_DIRECTIONS.length) %
      RELATIVE_DIRECTIONS.length;
    return RELATIVE_DIRECTIONS[index];
  }
docs: Returns the relative direction for a given direction, with reference to a
  another direction (reference direction).
  
  @param {string} direction The direction (absolute).
  @param {string} referenceDirection The reference direction (absolute).
  
  @returns {string} The relative direction.