Kokopu - v4.12.2
Kokopu is a JavaScript/TypeScript chess library. It implements the chess game rules, and provides tools to read/write the standard chess file formats (PGN, FEN, UCI, etc.).
https://www.npmjs.com/package/kokopu
Installation
- With NPM (or similarly with any package manager for Node.js such as Yarn):
npm install kokopu
- Without a package manager: download the single-file package
kokopu.zip, unzip it, and include either filekokopu.jsor filekokopu.min.jsin your HTML page.
Migrate to 3.x and 4.x
Versions 3.0.0 and 4.0.0 introduce some breaking changes with regard to the previous versions. To determine whether your codebase needs to be adapted or not when upgrading Kokopu, please look at:
- Migration guide to 4.x to upgrade from 3.x to 4.0.0 (or any subsequent version).
- Migration guide to 3.x and migration guide to 4.x to upgrade from 1.x or 2.x to 4.0.0 (or any subsequent version).
Main classes and functions
- Position: this class represents a chess position, i.e. the state of a 64-square chessboard with a few additional information (who is about to play, castling rights, en-passant rights). It exposes methods to generate the moves that can be played in the position, to check whether the position is check, checkmate or stalemate, to generate the FEN representation of the position, etc...
- Game: this class represents a chess game, with the move history, the position at each step of the game, the comments and annotations (if any), the result of the game, and some meta-data such as the name of the players, the date of the game, the name of the tournament, etc...
- Function pgnRead allows to parse a PGN file: this method returns Game objects representing the content of the file.
- Function pgnWrite allows to generate the PGN string corresponding to a Game object or an array of Game objects.
Example
const { Position } = require('kokopu');
// Create a new position, play some moves...
const position = new Position();
position.play('e4');
position.play('e5');
position.play('Nf3');
// Display an ASCII-art representation of the position.
console.log(position.ascii({ coordinateVisible: true }));
// +---+---+---+---+---+---+---+---+
// 8 | r | n | b | q | k | b | n | r |
// +---+---+---+---+---+---+---+---+
// 7 | p | p | p | p | | p | p | p |
// +---+---+---+---+---+---+---+---+
// 6 | | | | | | | | |
// +---+---+---+---+---+---+---+---+
// 5 | | | | | p | | | |
// +---+---+---+---+---+---+---+---+
// 4 | | | | | P | | | |
// +---+---+---+---+---+---+---+---+
// 3 | | | | | | N | | |
// +---+---+---+---+---+---+---+---+
// 2 | P | P | P | P | | P | P | P |
// +---+---+---+---+---+---+---+---+
// 1 | R | N | B | Q | K | B | | R |
// +---+---+---+---+---+---+---+---+
// a b c d e f g h
// b KQkq -
// List the available moves.
const moves = position.moves();
console.log(moves.map(move => position.notation(move)));
// [ 'a6', 'a5', 'b6', 'b5', 'c6', 'c5', 'd6','d5', 'f6', 'f5', 'g6',
// 'g5', 'h6', 'h5', 'Na6', 'Nc6', 'Qe7', 'Qf6', 'Qg5', 'Qh4', 'Ke7',
// 'Be7', 'Bd6', 'Bc5', 'Bb4', 'Ba3', 'Nf6', 'Nh6', 'Ne7' ]
Or directly within a HTML page, if no package manager is used:
<script src="kokopu.js"></script>
<script>
const position = new kokopu.Position();
position.play('e4');
position.play('e5');
// etc...
</script>