EventEmitter class in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

Node.js

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

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

AeventEmitter

BEmitter

CEventEmitter

DEvents

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase or misspelled class names like 'Emitter' or 'eventEmitter'.

Trying to import the whole module without destructuring.

You import the EventEmitter class exactly as EventEmitter from the 'events' module.

2fill in blank

medium

Complete the code to create a new instance of EventEmitter.

Node.js

const emitter = new [1]();

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Aevents

BeventEmitter

CEmitter

DEventEmitter

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase or incorrect class names.

Trying to call the module name instead of the class.

You create a new EventEmitter instance by calling new EventEmitter().

3fill in blank

hard

Fix the error in the code to add a listener for the 'start' event.

Node.js

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

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Aon

BaddListener

ConStart

Dlisten

Attempts:

3 left

💡 Hint

Common Mistakes

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

Confusing with 'addListener' which also works but is less common.

The correct method to add a listener is on. It listens for the event named 'start'.

4fill in blank

hard

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

Node.js

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 send events.

Using wrong event names like 'start' instead of 'data'.

You use emit to send out the event named data with the message.

5fill in blank

hard

Fill all three blanks to create an EventEmitter, add a listener for 'end', and emit the 'end' event.

Node.js

const [1] = new EventEmitter();
[1].[2]('end', () => {
  console.log('Finished');
});
[1].[3]('end');

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

Aemitter

Bon

Cemit

Dlistener

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Mixing up 'on' and 'emit' methods.

Using 'listener' which is not a method.

You create an instance named emitter, use on to listen for 'end', and emit to trigger it.