export const enum DirectionCardinalGeographicLetter { NORTH = 'N' , EAST = 'E' , SOUTH = 'S' , WEST = 'W' } export type HorizontalDirectionCardinalGeographicLetter = DirectionCardinalGeographicLetter . EAST | DirectionCardinalGeographicLetter . WEST ; export type VericalDirectionCardinalGeographicLetter = DirectionCardinalGeographicLetter . NORTH | DirectionCardinalGeographicLetter . NORTH ; export const isHorizontalDirectionCardinalGeographicLetter = ( symbol ) : symbol is HorizontalDirectionCardinalGeographicLetter => symbol === DirectionCardinalGeographicLetter . EAST || symbol === DirectionCardinalGeographicLetter . WEST ; export const isVericalDirectionCardinalGeographicLetter = ( symbol ) : symbol is VericalDirectionCardinalGeographicLetter => symbol === DirectionCardinalGeographicLetter . NORTH || symbol === DirectionCardinalGeographicLetter . SOUTH ; export const isDirectionCardinalGeographicLetter = ( marker ) : marker is DirectionCardinalGeographicLetter => isHorizontalDirectionCardinalGeographicLetter ( marker ) || isVericalDirectionCardinalGeographicLetter ( marker ) ;