Chess Core

A minimal, standalone chess logic implementation in TypeScript.

Features

• 🎯 Type-safe piece and board representations
• 🔧 Pure logic with no UI or DOM dependencies
• ♟️ Complete legal move calculation for all pieces
• 🏰 Full special rules support (castling, en passant, promotion)
• ✅ Check, checkmate, and stalemate detection
• 📝 FEN notation support (import/export game states)
• 🔄 Easily portable into any frontend or backend project
• 🧪 Unit test friendly architecture with comprehensive test coverage

Installation

Once published to npm:

npm install @chess-labs/core

Usage Example

import { initGameState, getLegalMoves, movePiece, gameStateToFen, fenToGameState } from '@chess-labs/core';

// Initialize a new game
const gameState = initGameState();

// Get legal moves for a piece
const moves = getLegalMoves({ row: 6, col: 4 }, gameState); // White pawn at e2

// Make a move
const newGameState = movePiece(
  { row: 6, col: 4 }, // from e2
  { row: 4, col: 4 }, // to e4
  gameState
);

// Convert to FEN notation
if (newGameState) {
  const fen = gameStateToFen(newGameState);
  console.log(fen); // "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1"

  // Load from FEN
  const loadedGame = fenToGameState(fen);
}

Architecture

src/
├── types.ts         # Core types (Piece, Board, Position)
├── board.ts         # Board initialization & utilities
├── board.spec.ts    # Board related tests
├── game.ts          # Game state, turn tracking, move execution
├── game.spec.ts     # Game logic tests
├── helper.ts        # Utility functions
├── helper.spec.ts   # Utility tests
└── moves/           # Per-piece movement logic

Roadmap

• ✅ Basic movement rules
• ✅ Special rules (castling, en passant, promotion)
• ✅ Check & checkmate detection
• ✅ FEN support (NEW!)
• PGN support
• AI opponent integration examples

Testing

npm run test

Unit tests are written with Vitest, covering all movement and rule logic.

Goals

• Write maintainable, testable TypeScript logic
• Decouple core engine from UI for maximum reusability
• Build as an open-source learning and portfolio project

Contributing

Pull requests, suggestions, and feedback are welcome! Please refer to the issues tab to get started.