Broadcasting to rooms in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a message to all clients in a specific room.

Express

io.to('[1]').emit('message', 'Hello room!');

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

Asocket

Bbroadcast

Cclient

Droom1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'socket' or 'client' instead of the room name.

Using 'broadcast' which sends to all except the sender.

The to method targets a specific room by its name, here 'room1'.

2fill in blank

medium

Complete the code to join a client socket to a room named 'chatroom'.

Express

socket.[1]('chatroom');

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

Ajoin

Bto

Cemit

Dleave

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'leave' which removes the socket from a room.

Using 'emit' which sends messages but does not join rooms.

The join method adds the socket to the specified room.

3fill in blank

hard

Fix the error in broadcasting a message to all clients except the sender.

Express

socket.[1].emit('message', 'Hello everyone!');

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

Ajoin

Bto

Cbroadcast

Demit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'to' which targets a specific room.

Using 'emit' directly which sends only to the sender.

The broadcast property sends to all clients except the sender.

4fill in blank

hard

Fill both blanks to broadcast a message to a specific room excluding the sender.

Express

socket.[1].to('[2]').emit('message', 'Hi room!');

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

Abroadcast

Bjoin

Croom1

Demit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'join' instead of 'broadcast' for the first blank.

Using 'emit' as a property instead of a method.

Use socket.broadcast.to('room1') to send to all in 'room1' except the sender.

5fill in blank

hard

Fill all three blanks to create a dictionary of room names and their client counts.

Express

const counts = { [1]: await io.in('[2]').allSockets().then(sockets => sockets.size), [3]: 0 };

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

AroomA

CroomB

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing room names between keys and values.

Using non-string keys or values.

This code counts clients in 'roomA' and initializes 'roomB' count to zero.