The method of the class of the application that I am creating in Typescript does not work as I expected.

//--snip--
export abstract class Piece {
  position —OptionalPosition;
  absolute readonly type —PieceKind;
  everMoved=false;
  constructor(readonly player:player, file:file,rank:rank){
    This.position = new Position (file, rank);
  }
  equal (piece:piece): boolean {
    return(
      !!piece.position &
      !! This.position &
      piece.type===this.type&&
      piece.position.equal (this.position)
    );
  }

  moveTo(position:Position, gameState:GameState){
    This.position=position;
    if(!this.everMoved){
      This.everMoved=true;
    }
  }

  removed() {
    this.position = null;
  }

  abstract canMoveTo (gameState:GameState): Position[];
}

export type GameState=Piece[];
// --snip--

export class King extensions Piece {
  readonly type = "king";
  moveTo(position:Position, gameState:GameState){    
    if(!this.everMoved&&(position.file==="C"||position.file==="G")}
      constrank=this.position?.rank;
      if(!rank){
        return;
      }
      constrookPosition=
        position.file==="C"
          ? new Position ("A", rank)
          : new Position("H",rank);
      constrook=gameState.find(piece)=>
        piece.position?equal(rookPosition)
      );
      if(!rook){
        return;
      }
      rook.position=
        position.file==="C"
          ? new Position ("D", rank)
          : new Position("F",rank);
    }
    super.moveTo(position, gameState);
  }
　// --snip--
}
// --snip--
constuseGame=()=>{
  const [gameState, setGameState] = useState<GameState> (defaultGameState);
  // --snip--
  commandClick=useCallback(
    (
      position: Position,
      gameState —GameState,
      player: Player,
      select —Select
    ) = > {
     // --snip--
              select.moveTo(position, gameState);
              setGameState(gameState);
 
// --snip--

rook.position=
        position.file==="C"
          ? new Position ("D", rank)
          : new Position("F",rank);