chess/js/pieces/Knight.js

/**
 * Knight.js - Knight piece implementation
 * Handles L-shaped movement pattern
 */

import { Piece } from './Piece.js';

export class Knight extends Piece {
    constructor(color, position) {
        super(color, position);
        this.type = 'knight';
    }

    /**
     * Get valid moves for knight
     * Knight moves in L-shape: 2 squares in one direction, 1 square perpendicular
     * @param {Board} board - Game board
     * @returns {Position[]} Array of valid positions
     */
    getValidMoves(board) {
        const moves = [];

        // All 8 possible L-shaped moves
        const moveOffsets = [
            [-2, -1], [-2, 1],  // Up 2, left/right 1
            [-1, -2], [-1, 2],  // Up 1, left/right 2
            [1, -2], [1, 2],    // Down 1, left/right 2
            [2, -1], [2, 1]     // Down 2, left/right 1
        ];

        for (const [dRow, dCol] of moveOffsets) {
            const targetRow = this.position.row + dRow;
            const targetCol = this.position.col + dCol;

            if (!this.isInBounds(targetRow, targetCol)) {
                continue;
            }

            const targetPiece = board.getPiece(targetRow, targetCol);

            // Can move to empty square or capture opponent piece
            if (!targetPiece || targetPiece.color !== this.color) {
                moves.push({ row: targetRow, col: targetCol });
            }
        }

        return moves;
    }
}