10 JavaScript Interview Questions and Answers

Prepare for a JavaScript interview with these questions and answers to common JavaScript interview questions!

[johnmurphy]

1.What is Scope? 0:25
2.What is Hoisting? 1:02
3.What is a closure? 1:57
4.What is functional programming? 2:55
5.What is the difference between synchronous and asynchronous code? 3:49
6. How can you determine if something is an array? 4:50
7. Higher Order Functions 5:18
8.What is the difference between an array and array-like object? 6:07
9.What is type coercion? 6:39
10.What is the difference between two way data binding and one way data flow? 7:09

[nathanthomas]

Talking about scope without including let and const seems strange to me.

[kamalyadav]

You are making good videos. Cheers for that.
Try to make some videos on real life projects, that would be beneficial to all of us, as learning by doing is a good way to understand some topics. For example: To do list, some small games, or any project you can think of :)

[kiva]

We are waiting for part 2 video JS interview questions :) You are a great content creator! Nice video, Nice explanations,

[Karan]

what about call, apply and bind. These are also being used much and if you can make some videos on es5+ that would be awesome like arrow functions, rest operators, map, filter and reduce. Also, a small video on inheritance through prototypes and class extends will be super cool :)

[Nikhilkumar-qdoq]

Very useful video. Can you please make another video on other interview questions.

[rexk]

A javascript programmer should know what "this" is.

[andriiauziak]

8. It's very confusing when you don't know that "arguments" is a keyword

[notdaveschannel]

The term array-like object always makes me laugh because it's nothing like an array. It's what your
Nan would get you for Christmas if you said you wanted an array.

[webpowers]

Wow, I hope it is multiple choice...I never, ever use these terms and completely forgot some of them...I would have totally failed a oral quiz on this...

[sanghamitranayak]

Can be added Prototype, inheritance, Call-Bind-Apply, Prototype Chain,

[amarthyaseshu]

in 2nd qn though its function expression, it is declared using var know, it won't get hoisted?

[fabricedufilssiyapdje]

Hey people and specially for the newbies out there. * DO NOT * use the construct at 5:06 . If I m in a point in my life where I have to check the type of a variable I my as well check if this variable is defined. so instead of doing : `if ( arr && arr.constructor === Array )` just use `Array.isArray(arr)` . General rule of thumb use this kind of static function construct and learn all of them, I said * ALL*.

[pekingopera]

I have watched a lot of your tutorial. Very good videos and fast pacing style!

On that mean stack contactlistapp, i was trying to add some validation logic but cannot get it to work. would like see how you do it? you post a new video, or simply update your git repository so I can view your code and download it. Many thanks!

[gjvidz]

Very helpful video. I'm going to use flashcards to help me memorize the answers.

[LukeryaPereprygova]

isnt var inside the function available outside?

[skillfulactor]

regarding your React video.


hey i had a question on the react video i was wondering, why did you put ipad iphone text on the left side simply because i wanted to know your thought process
on why you do what you do example like putting certain things in different places.

[mazthespaz]

question 6: Array.isArray(possibleArray)

[andrerothweiler]

So I can explain 8 of 10 questions right, so am I ready for a job?

[diwakarnrp]

Waiting for another video Js interview questions