Emitting and receiving messages in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to emit a message named 'greet' with the text 'Hello'.

Express

socket.[1]('greet', 'Hello');

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

Aemit

Blisten

Con

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' instead of 'emit' will not send a named event.

Using 'on' or 'listen' is for receiving messages, not sending.

The emit method sends a message with a specific name and data to the server or client.

2fill in blank

medium

Complete the code to listen for a message named 'chat' and log its data.

Express

socket.[1]('chat', (data) => {
  console.log(data);
});

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

Areceive

Bon

Csend

Demit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'emit' tries to send a message instead of listening.

Using 'send' or 'receive' are not valid socket methods.

The on method listens for incoming messages with a given name.

3fill in blank

hard

Fix the error in the code to correctly emit a message named 'update' with an object.

Express

socket.[1]('update', { status: 'ok' });

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

Alisten

Bsend

Con

Demit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' instead of 'emit' will not send the named 'update' event.

Using 'on' or 'listen' is for receiving, not sending.

To send a named message with data, use emit. Using send sends a default message without a name.

4fill in blank

hard

Fill both blanks to listen for a 'message' event and respond by emitting 'reply' with 'Received'.

Express

socket.[1]('message', (msg) => {
  socket.[2]('reply', 'Received');
});

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

Aon

Bemit

Csend

Dlisten

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' instead of 'emit' to send the reply.

Using 'emit' to listen or 'on' to send causes errors.

Use on to listen for the 'message' event, then emit to send the 'reply' event.

5fill in blank

hard

Fill all three blanks to emit 'start', listen for 'progress', and emit 'done' when progress reaches 100.

Express

socket.[1]('start');
socket.[2]('progress', (percent) => {
  if (percent === 100) {
    socket.[3]('done');
  }
});

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

Aemit

Bon

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' instead of 'emit' to send events.

Using 'on' to send events or 'emit' to listen causes errors.

Use emit to send 'start' and 'done' events, and on to listen for 'progress'.