JavaScript Questions

I post multiple choice JavaScript questions on my Instagram stories, which I'll also post here! Last updated: December 24th

From basic to advanced: test how well you know JavaScript, refresh your knowledge a bit, or prepare for your coding interview! 💪 🚀 I update this repo regularly with new questions. I added the answers in the collapsed sections below the questions, simply click on them to expand it. It's just for fun, good luck! ❤️

Feel free to reach out to me! 😊
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1. What's the output?

function sayHi() {
  console.log(name);
  console.log(age

…

10 JavaScript Quiz Questions and Answers to Sharpen Your Skills

Nick Scialli (he/him) on May 28, 2020

One way we can challenge ourselves to grow as JavaScript developers is to practice with quiz questions! The following questions are intended to be ...

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Saloni Yadav • May 28 '20

Well picked examples. I got something similar to question 8 in one of the js interviews. Also, could you explain question 5 a little more in terms of the event loop? Why promise.all returns in the same order... wouldn’t the event loop resolve based on the settimeout delay once the promise is returned? Thanks

HaiDV • May 29 '20 • Edited

Promise.all waits all promised to be resolved. That 's the simplest explanation

Saloni Yadav • May 29 '20

Yes. But my question is regarding the order of printing.

HaiDV • May 29 '20

It also ensure the order of data from promises. More info here: developer.mozilla.org/en/docs/Web/...

Thank you for the reference. :)

Mark Magyarodi • Jun 1 '20

the console.log is done only once after all promises are resolved, not for each timeout

Hibo • Jun 2 '20

Such a coincidence that I stumbled across the fact that comparing arrays that are exactly the same as each other in appearance (e.g. ([] === [])) would yield a false boolean result. So I'm glad to get an explanation for that! And it was a much simpler explanation than I thought haha.

Really great article thanks!

Larry Saytee • May 30 '20

Thanks.

Habdul Hazeez • May 29 '20

This repo comes to mind:

lydiahallie / javascript-questions

A long list of (advanced) JavaScript questions, and their explanations ✨

View on GitHub

Nick Scialli (he/him) • May 30 '20

Thanks! This looks like a great reference.

Mehedi Hasan Likhon • May 29 '20

Thank you!

You're welcome! I'll try to do some more next week

marjanb • May 28 '20

Nice work, excellent examples!

Thanks!

Praveen Saraogi • May 29 '20

Damn this proves, I've lot to learn about JS even after completing advance JS course from udemy.

Like any other language, JS has its fair share of idiosyncrasies. We all have more to learn!

Jorge • May 29 '20

You have a new susbcriber! Thanks for the quiz! I have learnt a little bit more of JS!

Wonderful! I hope to put out another version next week with more questions and aswers

Abel Lifaefi Mbula • May 30 '20

Nice and very beginner friendly.

Maxim • May 30 '20 • Edited

Answers to Sharpen Your Skills
beginner friendly

and this is what makes me cringe, cause fundamentals are fundamentals

Henry Ohanga • May 30 '20

Excellent work Nick!

Cătălin Anghel-Ursu • May 30 '20

Time for some mind food, and your JS quiz list was a tasty treat! You got a new follower.
Thanks for the nice work, Nick!

Shafkathullah Ihsan • May 30 '20

Cool!

Ememobong-dev • May 31 '20

i found this very helpful, i just began learning "Promise, Aysnc/Await" couldn't relate to the Promise question but i am 100% coming back to answer the quiz. Yup!! I love i saw this article. Thanks

Agathe Badia • Jul 6 '20

Thanks a lot! I love the idea of little quizzes like these ones. I really feel that I learn something and discover more things than those huge challenges x.x