Event-driven architecture in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the EventEmitter class from the 'events' module.

Express

const [1] = require('events');

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

AEmitterClass

BEventEmitter

CEmitter

DEvent

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect class names like 'Emitter' or 'Event'.

Forgetting to import from 'events' module.

The EventEmitter class is imported from the 'events' module to create event-driven behavior.

2fill in blank

medium

Complete the code to create a new instance of EventEmitter.

Express

const emitter = new [1]();

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AEventEmitter

BEmitter

CEvent

DEventClass

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect class names like 'Emitter' or 'Event'.

Forgetting the parentheses to create an instance.

You create a new event emitter by calling new EventEmitter().

3fill in blank

hard

Fix the error in the code to listen for the 'start' event.

Express

emitter.[1]('start', () => {
  console.log('Started');
});

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Alisten

BonStart

Con

DaddListener

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like 'listen' or 'onStart'.

Confusing event registration with event emitting.

The correct method to listen for events is on. It registers a callback for the event.

4fill in blank

hard

Fill both blanks to emit a 'data' event with a message.

Express

emitter.[1]('[2]', 'Hello World');

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Aemit

Bon

Cdata

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'on' instead of 'emit' to trigger events.

Using wrong event names.

Use emit to trigger an event. The event name here is data.

5fill in blank

hard

Fill all three blanks to create an event listener that logs the received message.

Express

emitter.[1]('message', ([2]) => {
  console.log([3]);
});

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

Aon

Bmsg

Demit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'emit' instead of 'on' to listen.

Using different variable names inconsistently.

Use on to listen for 'message' events. The callback receives the message as msg and logs it.