chess-easy

Description

This is a Typescript library for validating chess moves, generating possible moves, detection of check, checkmate and draw (Insufficient Material or Stalemate) and keeping state of the game using FEN notation.

Installation

npm i chess-easy

How to use

You can initialize game without any arguments, and that object will be initialized with starting game fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1". You can also pass different fen string and if it will be valid, game will be initialized with given Fen state.

import { Game } from "chess-easy

const chessGame = new Game();
const gameFromFen = new Game(`rnbqkbnr/pp1ppppp/8/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2`);

Game object methods

• getGameStateObject(): GameStateObject: Getting current state of game as object ex. {'e4': {piece: ChessPieces.KNHIGHT, color: COLORS.WHITE}, ...}
• isPromotionMove(from: string, to: string): boolean: Getting information if given move will cause promoting a pawn, useful for fronted, when you want to show some modal with choice of the promortion piece
• isDraw(): {isDraw: boolean, reason?: string}: Getting information if current game state is draw. Reason field exists if isDraw is true and can be one of 2 values: 'Stalemate', or 'Insufficient Material'
• move(from: string, to: string, promotion: PromotionPossibility = PromotionPossibility.QUEEN): boolean - This method validates if given move is correct and makes the move if it is valid. promotion argument is used only if move ends with promotion of a pawn and can have one of four values:
  • PromotionPossibility.ROOK
  • PromotionPossibility.BISHOP
  • PromotionPossibility.KNIGHT
  • PromotionPossibility.QUEEN
• generateFen(): string: Returns Fen string from current game state
• getNextColor(): "black" | "white": Returns string with next moving color.

Game object fields

  fen: string;
  gameState: GameState;
  movesNext: Colors;
  castlingAvailability: string;
  enPassantPossibility: string;
  halfMoveClock: number;
  fullMoveNumber: number;
  possibleMoves: PossibleMoves;
  isCheck: boolean;
  isCheckmate: boolean;
  isStalemate: boolean;
  isInsufficientMaterial: boolean;

Types

• enum ChessPieces {
    PAWN,
    BISHOP,
    KNIGHT,
    ROOK,
    QUEEN,
    KING,
  }

• enum Colors {
      WHITE,
      BLACK,
    }

• interface GameStateField {
    color: Colors;
    piece: ChessPieces;
  }

• type GameStateRow = (GameStateField | null)[];

• type GameState = GameStateRow[];

• type GameStateObject = {
    [key: string]: GameStateField;
  };

• type PossibleMoves = {
    [key: string]: string[];
  };

  Example

  If you want to see an example how this package can be used, you can see this chess service, than uses this package on both: frontend, and backend: https://github.com/mwisniewski00/Chess