Handling connection events in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to listen for new client connections on the server.

Express

const express = require('express');
const app = express();
const server = app.listen(3000);
server.on('[1]', (socket) => {
  console.log('A client connected');
});

Drag options to blanks, or click blank then click option'

Aconnecting

Bconnected

Cconnection

Dconnect

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'connect' instead of 'connection' causes the event not to fire.

The 'connection' event is emitted when a new client connects to the server.

2fill in blank

medium

Complete the code to handle when a client disconnects.

Express

server.on('connection', (socket) => {
  socket.on('[1]', () => {
    console.log('Client disconnected');
  });
});

Drag options to blanks, or click blank then click option'

Adisconnect

Bclose

Cend

Dexit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'disconnect' instead of 'close' will not catch client disconnects.

The 'close' event is fired when a client disconnects from the server socket.

3fill in blank

hard

Fix the error in the code to properly handle data received from a client.

Express

server.on('connection', (socket) => {
  socket.on('[1]', (data) => {
    console.log('Received:', data.toString());
  });
});

Drag options to blanks, or click blank then click option'

Adata

Binput

Cmessage

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'message' causes no data event to be caught on a raw socket.

The 'data' event is emitted when the socket receives data from the client.

4fill in blank

hard

Fill both blanks to create a server that logs when a client connects and disconnects.

Express

const net = require('net');
const server = net.createServer((socket) => {
  console.log('Client [1]');
  socket.on('[2]', () => {
    console.log('Client disconnected');
  });
});
server.listen(8080);

Drag options to blanks, or click blank then click option'

Aconnected

Bconnect

Cclose

Dconnection

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'connect' event on socket instead of 'close' for disconnection.

'connected' is a message to log, and 'close' is the event to listen for client disconnection.

5fill in blank

hard

Fill all three blanks to handle connection, data reception, and disconnection events properly.

Express

const net = require('net');
const server = net.createServer();
server.on('[1]', (socket) => {
  console.log('Client connected');
  socket.on('[2]', (data) => {
    console.log('Data:', data.toString());
  });
  socket.on('[3]', () => {
    console.log('Client disconnected');
  });
});
server.listen(9000);

Drag options to blanks, or click blank then click option'

Aconnection

Bdata

Cdisconnect

Dclose

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'disconnect' instead of 'close' for client disconnection event.

'connection' event fires when a client connects, 'data' when data arrives, and 'close' when client leaves.