A modern ES6 JavaScript draughts (checkers) library for move generation/validation, piece placement/movement, and draw detection - basically everything but the AI.
Inspired by chess.js
- ES6+ Modern JavaScript with comprehensive JSDoc type annotations
- Full draughts/checkers game logic including captures, promotions, and game ending conditions
- FEN notation support for position loading and saving
- PDN (Portable Draughts Notation) for game import/export
- Move validation and legal move generation
- TypeScript-friendly with detailed JSDoc types
- Node.js and Browser compatible
<script src="path/to/draughts.js"></script>npm install draughtsconst Draughts = require('draughts');
// or import Draughts from 'draughts'; // ES6 modules// Create a new game
const game = new Draughts();
// Play a random game
while (!game.gameOver()) {
const moves = game.moves();
const randomMove = moves[Math.floor(Math.random() * moves.length)];
game.move(randomMove);
}
console.log('Game over!');
console.log('Final position:', game.fen());
console.log('Game notation:', game.pdn());new Draughts([fen])
Creates a new draughts game instance.
// Start with default position
const game = new Draughts();
// Load a specific position using FEN
const game = new Draughts('W:W31-50:B1-20');Parameters:
fen(string, optional): FEN string to initialize the board position
.gameOver()
Returns true if the game has ended (no legal moves or no pieces remaining).
const game = new Draughts();
console.log(game.gameOver()); // false.turn()
Returns the current player's turn as a lowercase string.
const game = new Draughts();
console.log(game.turn()); // 'w' (white to move).inDraw()
Returns true if the game is drawn. (Currently always returns false - TODO)
console.log(game.inDraw()); // false.moves([square])
Returns an array of legal moves for the current position.
const game = new Draughts();
const moves = game.moves();
console.log(moves.length); // Number of legal moves
// Get moves for a specific square
const squareMoves = game.moves(35);.getLegalMoves(square)
Returns legal moves from a specific square.
const game = new Draughts();
const moves = game.getLegalMoves(35);
console.log(moves);
// [
// { jumps: [], takes: [], from: 35, to: 30, piecesTaken: undefined },
// { jumps: [], takes: [], from: 35, to: 31, piecesTaken: undefined }
// ].move(moveObject)
Attempts to make a move. Returns the move object if legal, false otherwise.
const game = new Draughts();
// ✅ Correct - Use move object
const result = game.move({ from: 35, to: 30 });
console.log(result);
// { jumps: [], takes: [], from: 35, to: 30, flags: 'n', piece: 'w' }
// ❌ Old string format no longer works
// game.move('35-30'); // Returns falseParameters:
moveObject(object): Move object withfromandtopropertiesfrom(number): Source square (1-50)to(number): Destination square (1-50)
.get(square)
Returns the piece at the given square.
const game = new Draughts();
console.log(game.get(35)); // 'w' (white piece)
console.log(game.get(25)); // '0' (empty square).put(piece, square)
Places a piece on the board.
game.clear();
game.put('w', 35); // Place white piece on square 35
console.log(game.get(35)); // 'w'Parameters:
piece(string): Piece type ('b', 'B', 'w', 'W')square(number): Target square (1-50)
.remove(square)
Removes and returns the piece at the given square.
const piece = game.remove(35);
console.log(piece); // 'w'
console.log(game.get(35)); // '0'.clear()
Clears the board to the starting position.
game.clear();.reset()
Resets the game to the initial starting position.
game.reset();.fen()
Returns the current position in FEN (Forsyth-Edwards Notation).
const game = new Draughts();
console.log(game.fen());
// 'W:W31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50:B1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20'.load(fen)
Loads a position from a FEN string.
const success = game.load('W:W31-50:B1-20');
console.log(success); // true if loaded successfully.validate_fen(fen)
Validates a FEN string without loading it.
const result = game.validate_fen('W:W31-50:B1-20');
console.log(result);
// { valid: true, error_number: 0, error: { code: 0, message: 'no errors' } }.ascii([unicode])
Returns an ASCII representation of the board.
const game = new Draughts();
console.log(game.ascii());
// +-------------------------------+
// | b b b b b |
// | b b b b b |
// | b b b b b |
// | b b b b b |
// | 0 0 0 0 0 |
// | 0 0 0 0 0 |
// | w w w w w |
// | w w w w w |
// | w w w w w |
// | w w w w w |
// +-------------------------------+
// Use Unicode symbols
console.log(game.ascii(true)); // Uses ♠, ♥, etc. symbols.history([options])
Returns the move history.
const game = new Draughts();
game.move({ from: 35, to: 30 });
game.move({ from: 19, to: 23 });
console.log(game.history());
// ['35-30', '19-23']
// Get verbose history with detailed move objects
console.log(game.history({ verbose: true }));
// [{ from: 35, to: 30, flags: 'n', piece: 'w', moveNumber: 1 }, ...].undo()
Undoes the last move.
const game = new Draughts();
const originalFen = game.fen();
game.move({ from: 35, to: 30 });
const undoneMove = game.undo();
console.log(game.fen() === originalFen); // true
console.log(undoneMove); // The move that was undone.header([key, value, ...])
Sets or gets PDN header information.
// Set headers
game.header('White', 'Alice', 'Black', 'Bob', 'Date', '2024-01-01');
// Get headers
console.log(game.header());
// { White: 'Alice', Black: 'Bob', Date: '2024-01-01' }.pdn([options])
Exports the game in PDN format.
const game = new Draughts();
game.header('White', 'Alice', 'Black', 'Bob');
game.move({ from: 35, to: 30 });
game.move({ from: 19, to: 23 });
console.log(game.pdn());
// [White "Alice"]
// [Black "Bob"]
//
// 1. 35-30 19-23Options:
maxWidth(number): Maximum line width for formattingnewline_char(string): Character to use for line breaks (default: '\n')
.parsePDN(pdn, [options])
Loads a game from PDN notation.
const pdn = `
[White "Alice"]
[Black "Bob"]
[Result "1-0"]
1. 35-30 19-23 2. 30-25 20-24
`;
const success = game.parsePDN(pdn);
console.log(success); // true if parsed successfully.captures()
Returns all possible capture moves for the current player.
const captures = game.captures();
console.log(captures); // Array of capture move objects.perft(depth)
Performance test function - counts total positions at given depth.
const nodeCount = game.perft(3);
console.log(`Positions at depth 3: ${nodeCount}`);The library includes comprehensive JSDoc type annotations for excellent TypeScript support:
interface MoveObject {
from: number; // Source square (1-50)
to: number; // Destination square (1-50)
flags: string; // Move flags: 'n', 'c', 'p'
piece: string; // Moving piece: 'b', 'B', 'w', 'W'
takes?: number[]; // Captured piece positions
jumps?: number[]; // Jump sequence positions
piecesTaken?: string[]; // Captured piece types
}
interface ValidationResult {
valid: boolean;
error?: {
code: number;
message: string;
};
fen: string;
}const game = new Draughts();
while (!game.gameOver()) {
const moves = game.moves();
if (moves.length === 0) break;
// Make a random move
const randomMove = moves[Math.floor(Math.random() * moves.length)];
const result = game.move(randomMove);
if (result) {
console.log(`Move: ${result.from}-${result.to}`);
}
}
console.log('Final position:', game.fen());// Load a specific position
const game = new Draughts('B:W31,32,33,34,35,36,37,38,39,40:B11,12,13,14,15,16,17,18,19,20');
console.log('Current turn:', game.turn());
console.log('Legal moves:', game.moves().length);
console.log('Captures available:', game.captures().length);
// Show the board
console.log(game.ascii());const game = new Draughts();
// Set up game metadata
game.header('Event', 'Friendly Match');
game.header('White', 'Player 1');
game.header('Black', 'Player 2');
game.header('Date', '2024-01-01');
// Play some moves
game.move({ from: 35, to: 30 });
game.move({ from: 19, to: 23 });
game.move({ from: 32, to: 28 });
// Export as PDN
console.log(game.pdn());Works in all modern browsers that support ES6 features:
- Chrome 51+
- Firefox 54+
- Safari 10+
- Edge 15+
For older browsers, use a transpiler like Babel.
Need a user interface? Try the draughtsboardJS library.
Contributions are welcome! Please feel free to submit a Pull Request.
This project is licensed under the MPL-2.0 License.