Async/await:UnhandledPromisejectionWarning:RangeError:超出最大调用堆栈大小

Question

在我的插座里。io应用程序，我正在尝试将房间中的一组用户发送到客户端，以便创建一个显示房间中所有用户的ul元素。文档中说，您可以使用以下代码返回给定命名空间和文件室中的所有套接字实例：

// return all Socket instances in the "room1" room of the "admin" namespace
const sockets = await io.of("/admin").in("room1").fetchSockets();

但是，它涉及到等待，这是我不太熟悉的。我只是把代码块放在一个async函数中，我不确定这是最好的方法。

io.of('/game').on('connection', socket => {
    console.log(`Socket ID: ${socket.id}`);
    
    const cookies = cookie.parse(socket.handshake.headers.cookie || "");
    console.log(cookies);
    const currentUser = cookies['current_user'];
    const roomName = cookies['room_name'];

    socket.username = currentUser;

    console.log(`${socket.username} connected to room "${roomName}"`);
    socket.on('disconnect', () => {
        console.log(`${socket.username} disconnected from room "${roomName}"`);
        io.of('/game').in(roomName).emit('leave', socket.username);
    });

    socket.join(roomName);

    (async() => {
        const usersInRoom = await io.of('/game').in(roomName).fetchSockets();
        console.log(`Number of users connected: ${usersInRoom.length}`);
        io.of('/game').in(roomName).emit('join', { username: socket.username, users: usersInRoom });
    })();
});

当我尝试运行此操作时，控制台中出现以下错误：

(node:9872) UnhandledPromiseRejectionWarning: RangeError: Maximum call stack size exceeded
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:28:19)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:9872) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:9872) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

我试着对此做了一些研究，发现了这个答案，建议将代码包装在try-catch块中。我已经做到了：

(async() => {
    try {
        const usersInRoom = await io.of('/game').in(roomName).fetchSockets();
        console.log(`Number of users connected: ${usersInRoom.length}`);
        io.of('/game').in(roomName).emit('join', { username: socket.username, users: usersInRoom });
    }
    catch(e) {
        console.log(e);
    }
})();

但是我仍然得到一个错误：

RangeError: Maximum call stack size exceeded
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:28:19)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)
    at hasBinary (<path>\node_modules\socket.io-parser\dist\is-binary.js:49:63)

我该怎么解决这个问题？任何帮助将不胜感激。

Answer 1

正如我们在评论中所讨论的，您不能发送整个套接字。通过套接字的io连接对象。io连接，因为它不能转换为JSON。

如果您真正想要发送的只是附加到socket.io对象的username属性的列表，那么您可以仅使用这些用户名创建一个数组。

更改此项：

io.of('/game').in(roomName).emit('join', { username: socket.username, users: usersInRoom });

对此：

const usernameList = usersInRoom.map(s => s.username);
io.of('/game').in(roomName).emit('join', { username: socket.username, users:  usernameList});