refactor: improve tic tac toe with region entity

src/samples/tic-tac-toe.ts

@@ -1,4 +1,4 @@
-import {createGameCommandRegistry, Part, Entity, entity, Region} from '@/index';
+import {createGameCommandRegistry, Part, Entity, entity, RegionEntity} from '@/index';
 
 const BOARD_SIZE = 3;
 const MAX_TURNS = BOARD_SIZE * BOARD_SIZE;
@@ -20,7 +20,7 @@ type TicTacToePart = Part & { player: PlayerType };
 
 export function createInitialState() {
     return {
-        board: entity<Region>('board', {
+        board: new RegionEntity('board', {
             id: 'board',
             axes: [
                 { name: 'x', min: 0, max: BOARD_SIZE - 1 },
@@ -89,15 +89,9 @@ function isValidMove(row: number, col: number): boolean {
     return !isNaN(row) && !isNaN(col) && row >= 0 && row < BOARD_SIZE && col >= 0 && col < BOARD_SIZE;
 }
 
-export function getBoardRegion(host: Entity<TicTacToeState>) {
-    return host.value.board;
-}
-
 export function isCellOccupied(host: Entity<TicTacToeState>, row: number, col: number): boolean {
-    const board = getBoardRegion(host);
-    return board.value.children.some(
-        part => part.value.position[0] === row && part.value.position[1] === col
-    );
+    const board = host.value.board;
+    return board.partsMap.value[`${row},${col}`] !== undefined;
 }
 
 export function hasWinningLine(positions: number[][]): boolean {
@@ -122,7 +116,7 @@ export function checkWinner(host: Entity<TicTacToeState>): WinnerType {
 }
 
 export function placePiece(host: Entity<TicTacToeState>, row: number, col: number, player: PlayerType) {
-    const board = getBoardRegion(host);
+    const board = host.value.board;
     const moveNumber = host.value.parts.length + 1;
     const piece: TicTacToePart = {
         id: `piece-${player}-${moveNumber}`,