Chess-easy NPM

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