Release 0.4.3 (#16)

* Update package-lock.json

* Document browser output

* Delete package-lock.json

Lockfile not needed

* Type cleanup

* Document `makeMove` param 3 `completeMove?`

* Minor cleanup

* Return undefined colour when cell is empty

Empty cells were being classified as black, leading to incorrect movement.

Fixes #15

* Restore package-lock.json

* Fix unchecked types

* Use nonnull assertion instead

Already checked for existence in the line above

* Improve board typing

* Add fen type

* Fix move list checking

* Version 0.4.3

.gitattributes

@@ -1,3 +1 @@
 * text=auto
-
-package-lock.json -diff

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "fenfurnace",
-	"version": "0.4.2",
+	"version": "0.4.3",
 	"description": "A chess engine designed to work entirely from a FEN position.",
 	"keywords": [
 		"chess",

readme.md

@@ -26,8 +26,9 @@ FenFurnace is available [on npm](https://www.npmjs.org/package/fenfurnace):
   - Check that a given move obeys the rules of chess.
 - `validation.pieceInWay(startCell, endCell)`
   - Check if there are any pieces between two cells.
-- `makeMove(startCell, endCell)`
+- `makeMove(startCell, endCell, completeMove)`
   - Attempt to move a piece; returns `false` if invalid.
+    If `completeMove` is `false`, no move will actually be made; instead the move will just be tested for validity.
 - `undoMove()`
   - Undoes and returns the last move.
 - `findAllMoves(cell)`
@@ -55,3 +56,5 @@ The following values are given in import `gameData`:
 ## Build
 
 Bundle local code for browser use with `npm run compile`.
+
+Functions are available under `window.fenFuncs`.

src/board/create-board.ts

@@ -1,23 +1,34 @@
 import gameData from '../variables';
-import { Cell, Colour } from '../types';
+import { toLowerCase, toUpperCase } from '../helpers';
+import { Cell, Colour, PieceID, FenParts, CastleString, Fen } from '../types';
+import { isWhite } from '../pieces';
 
 export default function createBoardArray(fenString: string): void {
-	const fenParts = fenString.split(' ');
-
-	const currentBoard = fenParts[0].split('/');
-	gameData.currentTurn = fenParts[1] as Colour;
+	const { fen, currentTurn, castling, enpassantSquare, halfMoveCount, moveNumber } = getFenParts(fenString);
 
 	gameData.castling = { w: { k: false, q: false }, b: { k: false, q: false } };
-	const castleString = fenParts[2];
+	const castleString = castling;
 	for (let i = 0; i < castleString.length; i++) {
-		const colour = castleString[i] === castleString[i].toUpperCase() ? 'w' : 'b' as Colour;
-		const side = castleString[i].toLowerCase() as ('k' | 'q');
+		const colour = isWhite(castleString[i] as PieceID) ? 'w' : 'b';
+		const side = toLowerCase(<'k' | 'q'>castleString[i]);
 		gameData.castling[colour][side] = true;
 	}
 
-	gameData.enpassantSquare = fenParts[3].toUpperCase() as Cell;
-	gameData.halfMoveCount = +fenParts[4];
-	gameData.moveNumber = +fenParts[5];
+	gameData.currentTurn = currentTurn;
+	gameData.enpassantSquare = enpassantSquare;
+	gameData.halfMoveCount = halfMoveCount;
+	gameData.moveNumber = moveNumber;
 
-	gameData.boardArray = currentBoard.map(val => val.replace(/[0-9]/g, n => '-'.repeat(+n)));
+	gameData.boardArray = fen.split('/').map(val => val.replace(/[0-9]/g, n => '-'.repeat(+n)));
+}
+
+function getFenParts(fenString: string): FenParts {
+	const fenParts = fenString.split(' ');
+	const fen = <Fen>fenParts[0];
+	const currentTurn = <Colour>fenParts[1];
+	const castling = <CastleString>fenParts[2];
+	const enpassantSquare = toUpperCase(<Cell>fenParts[3]);
+	const halfMoveCount = +fenParts[4];
+	const moveNumber = +fenParts[5];
+	return { fen, currentTurn, castling, enpassantSquare, halfMoveCount, moveNumber };
 }

src/board/create-fen.ts

@@ -1,6 +1,7 @@
+import { Fen } from '../types';
 import gameData from '../variables';
 
-export default function createFenFromBoardArray(): string {
+export default function createFenFromBoardArray(): Fen {
 	let fenString = '';
 	let blankSquares = 0;
 
@@ -44,5 +45,6 @@ export default function createFenFromBoardArray(): string {
 	fenString += ' ' + gameData.halfMoveCount;
 	//move number
 	fenString += ' ' + gameData.moveNumber;
-	return fenString;
+
+	return fenString as Fen;
 }

src/board/undo.ts

@@ -1,8 +1,8 @@
 import gameData from '../variables';
 import createBoardArray from './create-board';
 
-export default function undoMove(): string | undefined {
-	if (gameData.moveList.length === 0) return;
+export default function undoMove(): string | void {
+	if (gameData.moveList.length <= 1) return;
 	gameData.moveList.pop();
 	gameData.logList.pop();
 	const lastMove = gameData.moveList[gameData.moveList.length - 1];

src/helpers.ts

@@ -12,3 +12,11 @@ export function invertColour(colour: Colour): Colour {
 export function coordsToCell(x: number, y: number): Cell {
 	return indexToLetter(x) + y as Cell;
 }
+
+export function toUpperCase<T extends string>(str: T): Uppercase<T> {
+	return str.toUpperCase() as Uppercase<T>;
+}
+
+export function toLowerCase<T extends string>(str: T): Lowercase<T> {
+	return str.toLowerCase() as Lowercase<T>;
+}

src/pieces.ts

@@ -1,8 +1,9 @@
 import gameData from './variables';
 import { Colour, Cell, PieceID } from './types';
 
-export function getColour(cell: Cell): Colour {
+export function getColour(cell: Cell): Colour | undefined {
 	const piece = getPieceInCell(cell);
+	if (!piece) return;
 	return isWhite(piece) ? 'w' : 'b';
 }
 
@@ -39,7 +40,7 @@ export function add(piece: PieceID, cell: Cell): void {
 
 export function del(cell: Cell): void {
 	// console.log('Deleting piece from', cell);
-	const col = (parseInt(cell[0], 36) - 9);
+	const col = parseInt(cell[0], 36) - 9;
 	const row = 8 - (+cell[1]);
 	let str = gameData.boardArray[row];
 	gameData.boardArray[row] = str.substr(0, col - 1) + '-' + str.substr(col);

src/points.ts

@@ -7,7 +7,8 @@ export default function points(): { w: number, b: number } {
 		for (let cell in row.split('')) {
 			const colour = cell === cell.toUpperCase() ? 'w' : 'b';
 			const piece = cell.toLowerCase();
-			const pointsIncrease = { p: 1, m: 3, b: 3, r: 5, q: 9 }[piece] ?? 0;
+			const pointEquivs: Record<typeof piece, number> = { p: 1, m: 3, b: 3, r: 5, q: 9 };
+			const pointsIncrease = pointEquivs[piece] ?? 0;
 			points[colour] += pointsIncrease;
 		}
 	}

src/types.ts

@@ -10,3 +10,16 @@ export type Piece = 'pawn' | 'rook' | 'bishop' | 'knight' | 'queen' | 'king';
 export type PieceID = 'R' | 'r' | 'B' | 'b' | 'N' | 'n' | 'Q' | 'q' | 'K' | 'k' | '-';
 
 export type EndingStatus = false | 'stalemate' | 'checkmate';
+
+export type Fen = `${string} ${Colour} ${CastleString} ${Lowercase<Cell> | '-'} ${number} ${number}`;
+
+export type CastleString = `${'K' | ''}${'Q' | ''}${'k' | ''}${'q' | ''}`;
+
+export interface FenParts {
+    fen: Fen;
+    currentTurn: Colour;
+    castling: CastleString;
+    enpassantSquare: Cell;
+    halfMoveCount: number;
+    moveNumber: number;
+};

src/validation/all-moves.ts

@@ -16,7 +16,7 @@ export default function getAllMoves(cell: Cell): Board {
 		for (let j = 1; j <= 8; j++) {
 			const targetCell = coordsToCell(j, i);
 
-			if (makeMove(cell, targetCell, { isTest: true })) {
+			if (makeMove(cell, targetCell, false)) {
 				possibleSquares.push(targetCell);
 			}
 			createBoardArray(beforeState);

src/validation/is-check.ts

@@ -11,7 +11,7 @@ export default function isCheck(colour: Colour): boolean {
 			const testCell = coordsToCell(j, i);
 			const testPiece = pieces.getPieceInCell(testCell);
 			if (testPiece.toLowerCase() === 'k') {
-				const kingColour = pieces.getColour(testCell);
+				const kingColour = pieces.getColour(testCell)!;
 				kingCells[kingColour] = testCell;
 			}
 		}

src/validation/make-move.ts

@@ -4,24 +4,29 @@ import isCheck from './is-check';
 import * as pieces from '../pieces';
 import * as validation from './validation';
 import { Column, Row, Cell, PieceID } from '../types';
+import { invertColour } from '../helpers';
 
-export default function makeMove(startCell: Cell, endCell: Cell, { isTest }: { isTest?: boolean } = {}) {
-	// isTest=true: test the move instead of making it
+export default function makeMove(startCell: Cell, endCell: Cell, completeMove: boolean = true): string | false {
 
 	const piece = pieces.getPieceInCell(startCell);
 	const colour = pieces.getColour(startCell);
+	const startLetter = startCell[0] as Column;
+	const startNumber = +startCell[1] as Row;
+	const endLetter = endCell[0] as Column;
+	const endNumber = +endCell[1] as Row;
 	const beforeState = [...gameData.boardArray];
 	const events = { pieceCaptured: pieces.inCell(endCell), promoted: false, castled: false };
 
 	//must be same colour as move
-	if (colour !== gameData.currentTurn && !isTest) {
-		console.log('Failed to move', startCell, '->', endCell);
+	if (colour !== gameData.currentTurn) {
+		if (!completeMove) console.log('Failed to move', startCell, '->', endCell);
 		return false;
 	}
 
 	//validate castling
-	if (piece.toLowerCase() === 'k' && Math.abs(endCell.charCodeAt(0) - startCell.charCodeAt(0)) === 2 && (endCell[1] === startCell[1]) && !isCheck(colour)) {
-		const isKingside = endCell.charCodeAt(0) - startCell.charCodeAt(0) > 0;
+	const colDelta = endCell.charCodeAt(0) - startCell.charCodeAt(0);
+	if (piece.toLowerCase() === 'k' && Math.abs(colDelta) === 2 && (endLetter === startLetter) && !isCheck(colour)) {
+		const isKingside = colDelta > 0;
 		const side = isKingside ? 'k' : 'q';
 		if (gameData.castling[colour][side]) {
 			const file: Column = isKingside ? 'H' : 'A';
@@ -48,10 +53,10 @@ export default function makeMove(startCell: Cell, endCell: Cell, { isTest }: { i
 	else return false;
 
 	//promotion
-	let isBackRank = endCell[1] === (colour === 'w' ? '8' : '1');
+	const isBackRank = endNumber === (colour === 'w' ? 8 : 1);
 	if (piece.toLowerCase() === 'p' && isBackRank) {
 		if (!gameData.promotionPiece) {
-			console.error('NO PROMOTION PIECE FOUND');
+			console.error('No promotion piece found.');
 			gameData.boardArray = beforeState;
 			return false;
 		} else {
@@ -62,16 +67,15 @@ export default function makeMove(startCell: Cell, endCell: Cell, { isTest }: { i
 		}
 	}
 	//enpassant check (take old enpassant pawn && update enpassant square)
+	const enpassantNumber = endNumber + (colour === 'w' ? -1 : +1) as Row;
 	if (piece.toLowerCase() === 'p' && endCell === gameData.enpassantSquare) {
-		const enpassantNumber = colour === 'w' ? +endCell[1] - 1 : +endCell[1] + 1;
-		pieces.del(endCell[0] + enpassantNumber as Cell);
+		pieces.del(endLetter + enpassantNumber as Cell);
 		gameData.halfMoveCount = 0;
 		events.pieceCaptured = true;
 	}
-	const deltaLetter = Math.abs(+endCell[1] - +startCell[1]);
+	const deltaLetter = Math.abs(endNumber - startNumber);
 	if (piece.toLowerCase() === 'p' && deltaLetter === 2) {
-		const enpassantNumber = colour === 'w' ? (+endCell[1] - 1) : (+endCell[1] + 1);
-		gameData.enpassantSquare = endCell[0] + enpassantNumber as Cell;
+		gameData.enpassantSquare = endLetter + enpassantNumber as Cell;
 	} else {
 		gameData.enpassantSquare = '-';
 	}
@@ -86,7 +90,7 @@ export default function makeMove(startCell: Cell, endCell: Cell, { isTest }: { i
 	if (piece.toLowerCase() === 'k') {
 		gameData.castling[colour] = { k: false, q: false };
 	} else if (piece.toLowerCase() === 'r') {
-		const isKingside = startCell[0] === 'H';
+		const isKingside = startLetter === 'H';
 		const side = isKingside ? 'k' : 'q';
 		gameData.castling[colour][side] = false;
 	}
@@ -98,24 +102,24 @@ export default function makeMove(startCell: Cell, endCell: Cell, { isTest }: { i
 	else gameData.halfMoveCount++;
 
 	//change turn
-	gameData.currentTurn = gameData.currentTurn === 'w' ? 'b' : 'w';
+	gameData.currentTurn = invertColour(gameData.currentTurn);
 
 	//add to log
 	let logText = '';
 	if (events.castled === true) {
-		logText += endCell.charCodeAt(0) - startCell.charCodeAt(0) > 0 ? 'O-O' : 'O-O-O';
+		logText += colDelta > 0 ? 'O-O' : 'O-O-O';
 	} else {
 		if (piece.toLowerCase() === 'p' && events.pieceCaptured) logText += startCell[0].toLowerCase();
 		else if (piece.toLowerCase() !== 'p') logText += piece.toUpperCase();
 		if (events.pieceCaptured) logText += 'x';
 		logText += endCell;
 		if (events.promoted) logText += '=' + pieces.getPieceInCell(endCell).toUpperCase();
 	}
-	if (!isTest) gameData.logList.push(logText);
+	if (!completeMove) gameData.logList.push(logText);
 
 	//update fen and move list
-	let fen = createFenFromBoardArray();
-	if (!isTest) gameData.moveList.push(fen);
+	const fen = createFenFromBoardArray();
+	if (!completeMove) gameData.moveList.push(fen);
 
 	return fen;
 }

src/validation/validation.ts

@@ -11,8 +11,8 @@ export function validateMove(startCell: Cell, endCell: Cell): boolean {
 export function isValid(startCell: Cell, endCell: Cell): boolean {
 	let piece = pieces.getPieceInCell(startCell);
 	let colour: Colour = piece === piece.toUpperCase() ? 'w' : 'b';
-	let startNumber = parseInt(startCell[1]);
-	let endNumber = parseInt(endCell[1]);
+	let startNumber = +startCell[1];
+	let endNumber = +endCell[1];
 	let deltaNumber = Math.abs(endNumber - startNumber);
 	let deltaLetter = Math.abs(endCell.charCodeAt(0) - startCell.charCodeAt(0));
 	switch (piece.toLowerCase()) {
@@ -21,8 +21,7 @@ export function isValid(startCell: Cell, endCell: Cell): boolean {
 		case 'n':
 			return deltaNumber + deltaLetter === 3 && deltaLetter !== 0 && deltaNumber !== 0;
 		case 'k':
-			const singleMove = deltaLetter <= 1 && deltaNumber <= 1;
-			return (singleMove);
+			return deltaLetter <= 1 && deltaNumber <= 1;
 		case 'b':
 			return deltaLetter === deltaNumber;
 		case 'q':
@@ -44,14 +43,13 @@ export function pieceInWay(startCell: Cell, endCell: Cell): boolean {
 	let piece = pieces.getPieceInCell(startCell);
 	let colour = pieces.getColour(startCell);
 
-	let startNumber = parseInt(startCell[1]);
-	let endNumber = parseInt(endCell[1]);
+	let startNumber = +startCell[1];
+	let endNumber = +endCell[1];
 	let deltaNumber = Math.abs(endNumber - startNumber);
 	let startLetter = startCell[0];
 	let endLetter = endCell[0];
 	let deltaLetter = Math.abs(endCell.charCodeAt(0) - startCell.charCodeAt(0));
 
-
 	// determine direction
 	if (endLetter > startLetter) direction.l = 1;
 	else if (endLetter < startLetter) direction.l = -1;
@@ -64,18 +62,9 @@ export function pieceInWay(startCell: Cell, endCell: Cell): boolean {
 	switch (piece.toLowerCase()) {
 		case 'p': {
 			if (deltaLetter === 0) {
-				if (colour === 'w') {
-					invalidMove = pieces.inCell(startCell[0] + (startNumber + 1) as Cell);
-					if (deltaNumber === 2 && !invalidMove) {
-						invalidMove = pieces.inCell(startCell[0] + (startNumber + 2) as Cell);
-					}
-				}
-				else {
-					invalidMove = pieces.inCell(startCell[0] + (startNumber - 1) as Cell);
-					if (deltaNumber === 2 && !invalidMove) {
-						invalidMove = pieces.inCell(startCell[0] + (startNumber - 2) as Cell);
-					}
-				}
+				const directionMult = colour === 'w' ? +1 : -1;
+				const forwardNum = deltaNumber === 2 && !invalidMove ? 2 : 1;
+				invalidMove = pieces.inCell(startCell[0] + (startNumber + 1 * directionMult * forwardNum) as Cell);
 			}
 			return invalidMove;
 		}

src/variables.ts

@@ -1,10 +1,10 @@
-import { Colour, Cell, Board, PieceID } from './types';
+import { Colour, Cell, Board, PieceID, Fen } from './types';
 
 export default class GameData {
 	static castling = { w: { k: true, q: true }, b: { k: true, q: true } };
 	static boardArray: Board = [];
 	static enpassantSquare: Cell | '-' = '-';
-	static moveList: string[] = [];
+	static moveList: Fen[] = [];
 	static logList: string[] = [];
 	static currentTurn: Colour = 'w';
 	static halfMoveCount: number = 0;