kokopu/src/move_descriptor.ts

A JavaScript/TypeScript library implementing the chess game rules and providing tools to read/write the standard chess file formats.

/*!
 * -------------------------------------------------------------------------- *
 *                                                                            *
 *    Kokopu - A JavaScript/TypeScript chess library.                         *
 *    <https://www.npmjs.com/package/kokopu>                                  *
 *    Copyright (C) 2018-2025  Yoann Le Montagner <yo35 -at- melix.net>       *
 *                                                                            *
 *    Kokopu is free software: you can redistribute it and/or                 *
 *    modify it under the terms of the GNU Lesser General Public License      *
 *    as published by the Free Software Foundation, either version 3 of       *
 *    the License, or (at your option) any later version.                     *
 *                                                                            *
 *    Kokopu is distributed in the hope that it will be useful,               *
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of          *
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the            *
 *    GNU Lesser General Public License for more details.                     *
 *                                                                            *
 *    You should have received a copy of the GNU Lesser General               *
 *    Public License along with this program. If not, see                     *
 *    <http://www.gnu.org/licenses/>.                                         *
 *                                                                            *
 * -------------------------------------------------------------------------- */


import { Color, ColoredPiece, Piece, Square } from './base_types';


/**
 * Describe a legal chess move, with its characteristics.
 */
export abstract class MoveDescriptor {

    /**
     * @ignore
     */
    protected constructor() {}

    /**
     * Whether the current move is a castling move or not.
     */
    abstract isCastling(): boolean;

    /**
     * Whether the current move is a *en-passant* capture or not.
     */
    abstract isEnPassant(): boolean;

    /**
     * Whether the current move is a capture (either a regular capture or a *en-passant* capture) or not.
     */
    abstract isCapture(): boolean;

    /**
     * Whether the current move is a promotion or not.
     */
    abstract isPromotion(): boolean;

    /**
     * Origin square of the moving piece. In case of castling, this is the origin square of the king.
     */
    abstract from(): Square;

    /**
     * Destination square of the moving piece. In case of castling, this is the destination square of the king.
     */
    abstract to(): Square;

    /**
     * Color of the moving piece.
     */
    abstract color(): Color;

    /**
     * Type of the moving piece. In case of castling, the moving piece is considered to be the king.
     */
    abstract movingPiece(): Piece;

    /**
     * Color and type of the moving piece. In case of castling, the moving piece is considered to be the king.
     */
    abstract movingColoredPiece(): ColoredPiece;

    /**
     * Type of the captured piece.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a capture, i.e. if {@link isCapture} returns `false`.
     */
    abstract capturedPiece(): Piece;

    /**
     * Color and type of the captured piece.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a capture, i.e. if {@link isCapture} returns `false`.
     */
    abstract capturedColoredPiece(): ColoredPiece;

    /**
     * Origin square of the rook, in case of a castling move.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a castling move, i.e. if {@link isCastling} returns `false`.
     */
    abstract rookFrom(): Square;

    /**
     * Destination square of the rook, in case of a castling move.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a castling move, i.e. if {@link isCastling} returns `false`.
     */
    abstract rookTo(): Square;

    /**
     * Square containing the captured pawn, in case of a *en-passant* capture.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a *en-passant* capture, i.e. if {@link isEnPassant} returns `false`.
     */
    abstract enPassantSquare(): Square;

    /**
     * Type of the promoted piece, in case of a promotion.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a promotion, i.e. if {@link isPromotion} returns `false`.
     */
    abstract promotion(): Piece;

    /**
     * Color and type of the promoted piece, in case of a promotion.
     *
     * @throws {@link exception.IllegalArgument} if the current move is not a promotion, i.e. if {@link isPromotion} returns `false`.
     */
    abstract coloredPromotion(): ColoredPiece;

    /**
     * @ignore
     */
    toString(): string {
        let result = this.from() + this.to();
        if (this.isPromotion()) {
            result += this.promotion().toUpperCase();
        }
        else if (this.isCastling()) {
            result += 'O';
        }
        return result;
    }
}


/**
 * @deprecated Use `obj instanceof MoveDescriptor` instead.
 */
export function isMoveDescriptor(obj: unknown): boolean {
    return obj instanceof MoveDescriptor;
}