chessops/src/types.ts

Chess and chess variant rules and operations

export const FILE_NAMES = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'] as const;

export type FileName = (typeof FILE_NAMES)[number];

export const RANK_NAMES = ['1', '2', '3', '4', '5', '6', '7', '8'] as const;

export type RankName = (typeof RANK_NAMES)[number];

export type Square = number;

export type SquareName = `${FileName}${RankName}`;

export const ROLE_CHARS = ['q', 'n', 'r', 'b', 'p', 'k'] as const;

export type RoleChar = (typeof ROLE_CHARS)[number];

/**
 * Indexable by square indices.
 */
export type BySquare<T> = T[];

export const COLORS = ['white', 'black'] as const;

export type Color = (typeof COLORS)[number];

/**
 * Indexable by `white` and `black`.
 */
export type ByColor<T> = {
  [color in Color]: T;
};

export const ROLES = ['pawn', 'knight', 'bishop', 'rook', 'queen', 'king'] as const;

export type Role = (typeof ROLES)[number];

/**
 * Indexable by `pawn`, `knight`, `bishop`, `rook`, `queen`, and `king`.
 */
export type ByRole<T> = {
  [role in Role]: T;
};

export const CASTLING_SIDES = ['a', 'h'] as const;

export type CastlingSide = (typeof CASTLING_SIDES)[number];

/**
 * Indexable by `a` and `h`.
 */
export type ByCastlingSide<T> = {
  [side in CastlingSide]: T;
};

export interface Piece {
  role: Role;
  color: Color;
  promoted?: boolean;
}

export interface NormalMove {
  from: Square;
  to: Square;
  promotion?: Role;
}

export interface DropMove {
  role: Role;
  to: Square;
}

export type Move = NormalMove | DropMove;

export const isDrop = (v: Move): v is DropMove => 'role' in v;

export const isNormal = (v: Move): v is NormalMove => 'from' in v;

export const RULES = [
  'chess',
  'antichess',
  'kingofthehill',
  '3check',
  'atomic',
  'horde',
  'racingkings',
  'crazyhouse',
] as const;

export type Rules = (typeof RULES)[number];

export interface Outcome {
  winner: Color | undefined;
}