这是推荐的输入方式，要将类型缩小到success或error，应该使用if语句作为类型保护：

socket.emit(ClientActions.LOAD_GAME_STATE, (response: GameState | ErrorResponse) => {
    if ('<a property only in ErrorResponse>' in response) {
       // response is of type `ErrorResponse`
    } else {
       // response is of type `GameState`
    }
});

对于更具内聚性和可扩展性的类型，我建议如下（具体取决于您的实现）

type ResponseTypes = "success" | "error"; // You may want to get more specific/granular here

interface SocketResponse {
  type: ResponseTypes;
  // Other info on every socket response
}

interface SocketError extends SocketResponse {
  type: "error";
  errorMessage: string;
}

interface SocketGameState extends SocketResponse {
  type: "success";
  gameState: GameState;
}

你的原始代码会变成

socket.emit(ClientActions.LOAD_GAME_STATE, (response: SocketGameState | SocketError) => {
  if (response.type === "error") {
    ... // Narrows to SocketError
  } else {
    ... // Narrows to SocketGameState
  }
});

我认为这个解决方案将允许您最灵活地添加许多新类型的响应类型，同时以一致的、直观类型化的方式处理错误。