refactor: don't use this

src/samples/tic-tac-toe.ts

@@ -1,6 +1,6 @@
 import {
     createGameCommandRegistry, Part, createRegion, createPart, isCellOccupied as isCellOccupiedUtil,
-    registerGameCommand, IGameContext
+    IGameContext
 } from '@/index';
 
 const BOARD_SIZE = 3;
@@ -37,28 +37,29 @@ export type TicTacToeState = ReturnType<typeof createInitialState>;
 export type TicTacToeGame = IGameContext<TicTacToeState>;
 export const registry = createGameCommandRegistry<TicTacToeState>();
 
-registerGameCommand(registry, 'setup', async function() {
+async function setup(game: TicTacToeGame) {
     while (true) {
-        const currentPlayer = this.value.currentPlayer;
-        const turnNumber = this.value.turn + 1;
-        const turnOutput = await this.run<{winner: WinnerType}>(`turn ${currentPlayer} ${turnNumber}`);
+        const currentPlayer = game.value.currentPlayer;
+        const turnNumber = game.value.turn + 1;
+        const turnOutput = await turnCommand(game, currentPlayer, turnNumber);
         if (!turnOutput.success) throw new Error(turnOutput.error);
 
-        this.produce(state => {
+        game.produce(state => {
             state.winner = turnOutput.result.winner;
             if (!state.winner) {
                 state.currentPlayer = state.currentPlayer === 'X' ? 'O' : 'X';
                 state.turn = turnNumber;
             }
         });
-        if (this.value.winner) break;
+        if (game.value.winner) break;
     }
 
-    return this.value;
-});
+    return game.value;
+}
+registry.register('setup', setup);
 
-registerGameCommand(registry, 'turn <player:string> <turnNumber:int>', async function turn(turnPlayer: PlayerType, turnNumber: number) {
-    const playCmd = await this.prompt(
+async function turn(game: TicTacToeGame, turnPlayer: PlayerType, turnNumber: number) {
+    const playCmd = await game.prompt(
         'play <player> <row:number> <col:number>',
         (command) => {
             const [player, row, col] = command.params as [PlayerType, number, number];
@@ -69,23 +70,24 @@ registerGameCommand(registry, 'turn <player:string> <turnNumber:int>', async fun
             if (!isValidMove(row, col)) {
                 return `Invalid position: (${row}, ${col}). Must be between 0 and ${BOARD_SIZE - 1}.`;
             }
-            if (isCellOccupied(this, row, col)) {
+            if (isCellOccupied(game, row, col)) {
                 return `Cell (${row}, ${col}) is already occupied.`;
             }
             return null;
         },
-        this.value.currentPlayer
+        game.value.currentPlayer
     );
     const [player, row, col] = playCmd.params as [PlayerType, number, number];
 
-    placePiece(this, row, col, turnPlayer);
+    placePiece(game, row, col, turnPlayer);
 
-    const winner = checkWinner(this);
+    const winner = checkWinner(game);
     if (winner) return { winner };
     if (turnNumber >= MAX_TURNS) return { winner: 'draw' as WinnerType };
 
     return { winner: null };
-});
+}
+const turnCommand = registry.register('turn <player:string> <turnNumber:int>', turn);
 
 function isValidMove(row: number, col: number): boolean {
     return !isNaN(row) && !isNaN(col) && row >= 0 && row < BOARD_SIZE && col >= 0 && col < BOARD_SIZE;