监听事件

socket.on("details", (...args) => {
  // ...
});

socket.once("details", (...args) => {
  // ...
});

const listener = (...args) => {
  console.log(args);
}

socket.on("details", listener);

// and then later...
socket.off("details", listener);

// for a specific event
socket.removeAllListeners("details");
// for all events
socket.removeAllListeners();

socket.onAny((eventName, ...args) => {





    
  // ...
});

socket.prependAny((eventName, ...args) => {
  // ...
});

const listener = (eventName, ...args) => {
  console.log(eventName, args);
}

socket.onAny(listener);

// and then later...
socket.offAny(listener);

// or all listeners
socket.offAny();

const Joi = require("joi");

const userSchema = Joi.object({
  username: Joi.string().max(30).required(),
  email: Joi.string().email().required()
});

io.on("connection", (socket) => {
  socket.on("create user", (payload, callback) => {
    if (typeof callback !== "function") {
      // not an acknowledgement
      return socket.disconnect();
    }
    const { error, value }




    
 = userSchema.validate(payload);
    if (error) {
      return callback({
        status: "KO",
        error
      });
    }
    // do something with the value, and then
    callback({
      status: "OK"
    });
  });

});

io.on("connection", (socket) => {
  socket.on("list items", async (callback) => {
    try {
      const items = await findItems();
      callback({
        status: "OK",
        items
      });
    } catch (e) {
      callback({
        status: "NOK"
      });
    }
  });
});

require("events").captureRejections = true;

io.on("connection", (socket) => {
  socket.on("list products", async () => {
    const products = await findProducts();
    socket.emit("products", products);
  });

  socket[Symbol.for('nodejs.rejection')] = (err) => {
    socket.emit("error", err);
  };
});