Why timing matters in Node.js in Node.js - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print a message after 1 second using setTimeout.

Node.js

setTimeout(() => { console.log([1]); }, 1000);

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

A"Hello after 1 second"

BHello after 1 second

Cconsole.log('Hello')

D1000

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string

Passing a number instead of a string

Trying to call console.log inside the argument

The message to print must be a string inside quotes.

2fill in blank

medium

Complete the code to run a function repeatedly every 2 seconds using setInterval.

Node.js

setInterval([1], 2000);

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

Aconsole.log

Bconsole.log('Repeat')

C() => console.log('Repeat')

D'Repeat'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string instead of a function

Calling console.log immediately instead of passing a function

Passing console.log without calling it

setInterval expects a function as the first argument, so we use an arrow function.

3fill in blank

hard

Fix the error in the code to correctly delay the execution of greet function by 3 seconds.

Node.js

function greet() { console.log('Hi!'); } setTimeout([1], 3000);

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

Agreet()

Bgreet

C() => greet()

DsetTimeout(greet, 3000)

Attempts:

3 left

💡 Hint

Common Mistakes

Calling the function immediately with parentheses

Passing a string instead of a function

Using setTimeout inside setTimeout

Passing the function name without parentheses delays execution correctly.

4fill in blank

hard

Fill both blanks to create a timer that stops after 5 seconds.

Node.js

const timer = setInterval(() => { console.log('Tick'); }, [1]); setTimeout(() => { clearInterval([2]); console.log('Stopped'); }, 5000);

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

A1000

Btimer

C500

DsetInterval

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong interval time

Passing wrong variable to clearInterval

Confusing setInterval with clearInterval

Use 1000 ms for interval and clearInterval with the timer variable to stop it.

5fill in blank

hard

Fill all three blanks to create a promise that resolves after 2 seconds with message 'Done'.

Node.js

const myPromise = new Promise(([1], [2]) => { setTimeout(() => { [3]('Done'); }, 2000); });

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

Aresolve

Breject

Cconsole.log

Dcallback

Attempts:

3 left

💡 Hint

Common Mistakes

Using console.log instead of resolve

Swapping resolve and reject

Not calling resolve inside setTimeout

Promises use resolve and reject functions; resolve is called after timeout.