Monkfish

a chess engine in typescript for Deno.

Demo: https://monkfish-demo.vercel.app/

Getting Starting

for Node

npm i monkfish

and then

import { Game } from 'monkfish'

const game = new Game()

game.move({ from : 'a2', to: 'a3' })

const aiMove = game.bestMove()
game.move(aiMove)

for Deno

import { Game } from 'https://deno.land/x/monkfish@0.2.0/mod.ts'

const game = new Game()

API

.move(move: MoveObject): void

game.move({ from : 'a2', to: 'a3' }) // move piece on a2 to a3
game.move({ from : 'a7', to: 'a8', promotion: 'Q' }) // move piece on a7 to a8 and promote to queen

.undo(): void

undo the last move

const game = new Game()
game.move({ from : 'a2', to: 'a3' })
game.fen() // "rnbqkbnr/pppppppp/8/8/8/P7/1PPPPPPP/RNBQKBNR b KQkq - 1 1"
game.undo()
game.fen() // "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"

.sideToMove(): 'w' | 'b'

const game = new Game()
game.sideToMove() // 'w'

.load(fen: string): void

game.load('rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq - 1 1')

.isGameOver(): boolean

const game = new Game('r1bqkbnr/pppppQ2/2n3p1/7p/2B1P3/8/PPPP1PPP/RNB1K1NR b kq - 0 1')
game.isGameOver() // true

const game = new Game('r2qkb2/p1p2p2/2npbnpr/1p2p2p/2B1P2P/NPP2N1R/P2P1PP1/R1BQK3 b q - 50 30')
game.isGameOver() // true

.isInCheck(): boolean

const game = new Game('r1bqkbnr/pppppQ2/2n3p1/7p/2B1P3/8/PPPP1PPP/RNB1K1NR b kq - 0 1')
game.isInCheck() // true

.fen(): string

const game = new Game()
game.fen() // "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"

.status(): string

const game = new Game()
game.status() // "playing"

const game = new Game('r2qkb2/p1p2p2/2npbnpr/1p2p2p/2B1P2P/NPP2N1R/P2P1PP1/R1BQK3 b q - 50 30')
game.status() // "draw by fifty rule"

const game = new Game('r1bqkbnr/pppppQ2/2n3p1/7p/2B1P3/8/PPPP1PPP/RNB1K1NR b kq - 0 1')
game.status() // "white won by checkmate"

.claimDraw(): Boolean

claim draw once in a threefold repetition state.
will return true if in threefold repetition state and game will be set to draw, otherwise will return false.

// once in a threefold repetition state
game.claimDraw() // true
game.status() // "draw by threefold repetition"
game.isGameOver() // true

.pieceOnSquare(square: BoardPositionNotation): string | null

const game = new Game()
game.pieceOnSquare('a2') // "P"
game.pieceOnSquare('b8') // "n"
game.pieceOnSquare('b4') // null

.possibleMoves(): BoardPositionNotationMove[]

get all possible moves for the current side

const game = new Game()
game.possibleMove() // [{ from: "b1", to: "c3", promotion: null, piece: "N", castling: null },
  // { from: "b1", to: "a3", promotion: null, piece: "N", castling: null },
  // { from: "g1", to: "h3", promotion: null, piece: "N", castling: null },
  // { from: "g1", to: "f3", promotion: null, piece: "N", castling: null },
  // { from: "a2", to: "a3", promotion: null, piece: "P", castling: null },
  // ...]

.possibleMovesForPosition(position: BoardPositionNotation): BoardPositionNotationMove[]

et all possible moves for a certain square

const game = new Game()
game.possibleMovesForPosition('b1') // [{ from: "b1", to: "c3", promotion: null, piece: "N", castling: null }, { from: "b1", to: "a3", promotion: null, piece: "N", castling: null }]

.bestMove(depth: number = 5): BoardPositionNotationMove | null

try to get the best possible move given a depth to search in

const game = new Game()
game.bestMove('b1') // { from: "b1", to: "c3", promotion: null, piece: "N", castling: null }

TODO:

• more tests
• algebraic notation moves