I'm building a chess-related application using nodejs. I've been trying to use chess.js
as much as I can but I think I've hit a roadblock in terms of functionality. Before extending that functionality, I wanted to make sure that there wasn't another tool that can do what I need.
I'm looking for a way to convert a PGN string into a list of FEN moves. I was hoping to use load_pgn()
in chess.js to load the moves into the object and then loop over each move and invoke the fen()
function to output the current FEN. However, chess.js doesn't seem to have a way to walk through the moves in a game. Unless I'm missing something.
I'd rather not have to get into parsing strings, but will if I have to. Any suggestions?
Solution:
also see efirvida's answer below for a solution
Something like this (untested) seems to work. The function accepts a Chess
object created with chess.js
that already has a PGN loaded into it.
function getMovesAsFENs(chessObj) {
var moves = chessObj.history();
var newGame = new Chess();
var fens = [];
for (var i = 0; i < moves.length; i++) {
newGame.move(moves[i]);
fens.push(newGame.fen());
}
return fens;
}
Take a look to the github page .load_pgn
link
var chess = new Chess();
pgn = ['[Event "Casual Game"]',
'[Site "Berlin GER"]',
'[Date "1852.??.??"]',
'[EventDate "?"]',
'[Round "?"]',
'[Result "1-0"]',
'[White "Adolf Anderssen"]',
'[Black "Jean Dufresne"]',
'[ECO "C52"]',
'[WhiteElo "?"]',
'[BlackElo "?"]',
'[PlyCount "47"]',
'',
'1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4 Bxb4 5.c3 Ba5 6.d4 exd4 7.O-O',
'd3 8.Qb3 Qf6 9.e5 Qg6 10.Re1 Nge7 11.Ba3 b5 12.Qxb5 Rb8 13.Qa4',
'Bb6 14.Nbd2 Bb7 15.Ne4 Qf5 16.Bxd3 Qh5 17.Nf6+ gxf6 18.exf6',
'Rg8 19.Rad1 Qxf3 20.Rxe7+ Nxe7 21.Qxd7+ Kxd7 22.Bf5+ Ke8',
'23.Bd7+ Kf8 24.Bxe7# 1-0'];
chess.load_pgn(pgn.join('\n'));
// -> true
chess.fen()
// -> 1r3kr1/pbpBBp1p/1b3P2/8/8/2P2q2/P4PPP/3R2K1 b - - 0 24
something like
moves = chess.history();
var chess1 = new Chess();
for (move in moves){
chess1.move(move);
fen = chess1.fen()
}