JavaScript Interview Questions & Answers | JavaScript Interview Questions
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- Опубліковано 21 лип 2024
- For more JavaScript Q&A videos visit www.questpond.com
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00:00 Introduction
2:50 Question 1:- Why do we call JavaScript as dynamic language?
3:54 Question 2:- how does JavaScript determine data types ?
4:44 Question 3:- What is typeof functions?
4:44 Question 4:- How to check data type in JavaScript ?
5:21 Question 5:- What are different datatypes in JavaScript ?
7:51 Question 6:- Explain Undefined Data types ?
8:36 Question 7:- What is Null ?
9:02 Question 8:- Differentiate between Null and Undefined ?
9:41 Question 9:- Explain Hoisting ?
10:51 Question 10:- Are JavaScript initialization hoisted ?
11:39 Question 11:- What are global variables ?
12:06 Question 12:- What are the issues with Global variables ?
12:30 Question 13:- What happens when you declare variable with out VAR ?
13:30 Question 14:- What is Use Strict ?
13:30 Question 15:- How to force developers to use Var keyword ?
14:26 Question 16:- How can we handle Global Variables ?
14:26 Question 17:- How can we avoid Global variables ?
16:14 Question 18:- What are Closures ?
19:16 Question 19:- Why do we need Closures ?
22:52 Question 20:- Explain IIFE ?
24:40 Question 21:- What is the use of IIFE ?
24:40 Question 22:- What is name collision in global scope ?
24:40 Question 23:- IIFE vs Normal Function?
28:12 Question 24:- What are design patterns ?
28:52 Question 25:- Which is the most used design pattern?
29:03 Question 26:- What is module Pattern and revealing module pattern ?
33:57 Question 27:- What are the various ways to create JavaScript objects?
35:55 Question 28:- How can we do inheritance in JavaScript ?
35:55 Question 29:- What is prototype in JavaScript ?
35:55 Question 30:- Explain Prototype chaining ?
43:41 Question 31:- What is Let Keyword?
45:52 Question 32:- Are Let variables hoisted ?
48:27 Question 33:- Explain Temporal Dead Zone ?
51:28 Question 34:- Let vs Var
58:12 Question 35:- String Concatenation and Arithmetic puzzle
Question 36 :- What is class in ES6 ?
Question 37 :- So with class Keyword does it imply JavaScript is a OOP language ?
Question 38 :- Differentiate between class and normal function ?
Question 39 :- What is a Arrow function ?
Question 40 :- Why do we use Arrow function ?
Question 41 :- Differentiate between Arrow vs Normal Function ?
Question 42 :- Does Arrow function create its own this ?
Question 43. Explain Synchronous execution ?
Question 44. What is a call Stack ?
Question 45. What is a blocking call ?
Question 46. How to avoid blocking calls ?
Question 47. Explain Asynchronous execution ?
Question 48. Synch vs Asynch ?
Question 49. How can we do Asynch calls ?
Question 50. What is a thread ?
Question 51. Explain Multi-threading ?
Question 52. Is JavaScript Multi-threaded ?
Question 53. Then how does Settimeout run ?
Question 54. What is a WebAPI/Browser API ?
Question 55. What is a Event loop and callback queue?
Question 56. Eventloop and Callback code question
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Please add React interview questions and answers also. Thank you in advance
hello sir, i know from your voice only you are very senior but can u make teaching vedios like tutorials for react,angular,next.js anything u waana do is fine. i would like to learn from u not only questions but the whole course itself. IDK maybe i am being greddy but do think on it if u time sir. thank you BTW for your amazing video loved it
You can miss Asynchronous JavaScript like callbacks and promises, timeout functions
One more thing I would like to add
1+1+”4” gives 24
“4”+1+1 gives 411
Js works from left to right and if the starting is string then it takes upcoming values as string as well
thanks bro
"200"+(2+3+4)
"2009"
1+1+ +'4 '= 6
Thanks for detailed Q& A.
Good clarity in list :
1. dynamic language.
2. Hositing behavior,
3. global variable,
4. use strict,
5. closure,
6.IIFE
7. design patterns
8.create object -
9. Inheritance - prototypal inheritance.
10. let keyword - temporal dead zone.
11. let vs var
I LOVE THAT U REPEAT THE ANSWERS 2-3-4 TIMES. IT REALLY HELP ME TO UNDERSTAND !!!
THANKS YOU !!!
This video is Gold for interview prep. It gives you clarity on the concepts so that you don't just blabber things during the interview.
If you were my mentor, i will have the potential to get into any company as i prefer.... God level details... Now my confidence level is 100% thank you so much... And that closure concept is mind blower
I am grateful to find this channel. Thank you for such an awesome explanation.
Hi Sir, your questions helps in cracking interviews. Thanks very much!
Most await for part-2 Advance JS interview questions
Thanks a lot. ❤️
. waiting for part 2
Shared this on all the major platforms
Hi, on the question of what is the difference between a normal function and an IFFE, can I say that a normal function is not necessarily executed immediately?
Nice explanation.
You have explained all core concepts very well that takes JS knowledge into next level.
You have explained that why those concepts are used and which problems are resolved by them, which is very good.
Thank you sir.. good explanation with examples.
Wow you have just amazing Technic to explain tough concepts a big thank you
Thank you sir shiv, you make the material with great effort.
very amazing explanation given by sir. it is very helpful for me ,Thank you
i love your courses - very concise and pretty broad ranging
Hello sir, I am having doubt on normal and IIFE function.
To avoid name collision we can use IIFE, but IIFE is a function which is invoking immediately once page loads right? So what if I want a function which I don't want to immediately invoked but should not have name collision? So which function I should use now?
I am your new follower. Sir, if you could please upload real-time projects like creating websites from scratch to deployment, also creating desktop application , web application and mobile application so that we will be grateful to you.
Thank you for this video. Please make video of React js interview questions
Videos... Quest with explanation was very nice... Thank u sir
Thank you sir for this video , you explained very well sir 👍👍
Bro, you are an amazing programming tutor. Thank you 👏
good explanation sir , Its very helpful.
Thanks a lot sir ,This helps me for crack interview.
Geat explaination every topics.
great video it clears most of the concepts in a shorts span. but I didn't get e book on my mail
Hello Sir, Nice explaination. i need some more topics from you. that is hot in market.
Azure Interview Question
AWS Interview Question,
Web API,
Design Patterns,
And more advance Angular Interview Questions.
No one not explaining like you. now a days these topics are very important.
You are awesome 😎 Kindly make more videos. This is really helpful 🙏
sir your way of explanation is so easy to understand thanks for the video🙏
Good Explanation ,Thank you sir
❤️❤️❤️❤️❤️Love to @Shivprasadkoirala sir and Quest family , it's very helpful
Many Thanks for your effort
Thanks a lot Sir. 🙏👏
Great video…. Thank you!❤
Write a function called do_allocation(number_of_people, number_of_buses)
The function should return a list of number of people who can get into the next bus that comes in based on the following logic:
Each bus’s capacity is the sum of the capacities of the previous two buses.
Once all the people get in, then the buses can continue, but will have 0 people inside it.
This is the case when the number of people are less and there are more buses. So after all the people are already boarded, then the remaining buses will have 0 people boarding.
The output of the function is an array/list with the same length as number_of_buses.
The total of this output array/list should be less than or equal to the number_of_people.
The first bus’ capacity can be set to 1 by default.
E.g.
Def do_allocation(number_of_people, number_of_buses):
…. Your code….
Return array[number of people got into first bus, number of people got into second bus, …. , number of people who got into last bus]
Really usefull,. Thx ☺️
Hi!
On regards to inheritance, correct me if I'm wrong... You can also do inheritance by class using the "extends" keyword. So I believe that is important to mention, or maybe I missed that part.
I think extends keyword we use when we use ES6 syntax when we use classes. but here the mostly plain JavaScript inheritance, that is the reason it is mostly on prototype i believe.
When will you post the second part of this course
is multiple inheritance allowed using prototype ?
Very helpful. Please make a video on React-Redux & GraphQl Interview Tips
Very nice👍
Thanks a lot sir for great value addition, all are amazing videos.
Thank you...
Good explanation
Thank you sir
18:42 : Is Increment a closure function? Or ClosureFunction?
Your videos are really informative.. And the way you explain is also crispy and understandable. Thank you so much for the effort..❤
wow really useful video!
awesome stuff
Thanks so much
Nice video sir.
Thanks bro, very helpful video ! :)
Thank you for appreciation, Happy job hunting..!
great sir 🤩
You have explained everything in kantaap manner.... Thank you so much for that
I shared your video on Linkedin and FB. Can I get the PDF you mentioned?
43:25 what is that last para..and your definition is different from what's written
Sir please make a video on React js Interview
You are gem💎
Please provide video of react and redux interview questions
Please provide nodejs video as well
1st of all thank you for this but
sir Encapsulation mean bunding data with function as a component and you given example for abstraction not for encapsulation
abstruction mean what we want to show and what we want to hide.. sir i want reply plese reply me
Please do video on EventLoop
Please make a video about React Js.
Pls make video on react js
Thanks, i learned a lot. I have an interview today for a full stack developer position
Good Luck
How was it brother
@@lokeshvasnik6872 it was good. They asked questions related to React JS like, what is higher order component, pure component, why do we use key prop.
From which portal where you able to get interview?
Nice question
sir what about second part.....???????????
Please note IIFE means
immediately invoked function expression, or IIFE (pronounced iffy),
Primitive and non primitive and in non primitive we have array and object…
I suppose undefined means variables is being declared but type is not defined and null means variables is defined with the type was well but the value is not set yet.
Example : var x --> undefined. no type defined yet
var y = null -> type is defined but the value is null.
Please correct if I am wrong
Actually, undefined is itself a type in javascript. So, in var x; x would still have a type and that type is undefined.
What is difference between below code without IIFE i can achieve same thing with below code
var namespaced = function IffeFunc() {
function Customer() {
return "Some customer"
}
function CustomerInvoices() {
return "Invoices"
}
return {
Customer
}
};
let name = namespaced().Customer(); // "Some customer"
best
can you send me pdf , Angular questions and answers and this pdf ?
How to get free access of other parts ?
If i buy 399/month membership will i get all interview questions and video and pdf too like mvc,c#, javascript videos and pdf
Sir do you have a twitter/linkedin account which I can tag while sharing this video?
Yes, our social media accounts are flashed on the youtube channel as well ua-cam.com/users/questpondvideosvideos
inp = [
{name: 'firstname', value: 'johndoe'},
{name: 'age', value: '28'},
{name: 'language', value: 'English'},
{name: 'language', value: 'Tamil'},
{name: 'language', value: 'Hindi'},
]
Expected Output -
{
firstname: 'johndoe',
age: '28',
language: ['English', 'Tamil', 'Hindi']
}
How to solve this?
Please provide link to the 2nd part
JavaScript Q&A Part 1 to Part 4 you can avail from here www.questpond.com/javascript-interview-questions-and-answers/cid87
is there a second part of this? can someone please share the link?
I see its paid.
shared it on my LinkedIn
@@roshanjha1859 Yes next part is available under paid subscription.
@@roshanjha1859 after sharing send email with the link from your linkedin timeline and get ebook and source of part 1 video. Thank You
one question for null vs undefined, can't we assign undefined to a variable? if so, then it's not different on that point
🎉👍
I don't get why in video created in 2022 we still see a "var" ??? I believe no-one is using it anymore, or am I wrong!?
Its a interview questions video and later we have talked about difference between var vs let.
FYI Devs still use var , it has its own place.
typeof null is object
Hi Sir, could you please send the source code ?
You can get it over email, just follow the instructions given in the video. Thank You
I tweeted this video
thanks from Ukraine
where is the 2nd part?
JavaScript Part 1 to Part 3 is available here - www.questpond.com/javascript-interview-questions-and-answers/cid87
Where is the second part Ive been waiting a year
Javascript Q&A series you can get from Questpond - www.questpond.com/javascript-interview-questions-and-answers/cid87
sir part 2 link plz
JavaScript Interview Q&A videos are available on Questpond - www.questpond.com/javascript-interview-questions-and-answers/cid87
Where is part2
JavaScript Q&A Part 2 will be released soon on www.questpond.com/
where us part 2
?
In progress, soon it will be available in questpond subscription.
Did you just say that let is hoisted? Where is this mentioned. Show me the documentation provided by officials.
No i did not say Let is hoisted , Can you show me the exact time stamp if i said that ?
@@questpondvideos at 49:30.
@@questpondvideos at 46:59 and 47:31
@@questpondvideos at 47:56 and 48:12
@@questpondvideos I have seen this mistake a lot. But we all know let is not hoisted. Only var is hoisted.
Only 20-30%?
yes....thats minimum :-)
Thanks for the video. 'use strict' does more than just checking for var variables. If anyone is interested, google it ;)
Thank you sir
Thanks alot sir
Thank you sir