0:33 - what is prototypal inheritance 2:58 - what is the difference between function declaration & function expression 4:21 - what is promises and why do we use it 6:43 - setTimeout() 8:23 - what is closure and how do we use it

Nice tutorial before appearing for JS interview. I had gone through a few interviews and was asked most of these questions and also them: 1. Spread Operator 2. Bind, Call, Apply in JS 3. Array Questions (deep copy and shallow copy of array using assign;also map property used many a times) 4. Ques based on Object Keys Hope it helps! (I would appreciate if you make some short video on these topics as well)

5)When do we use Arrow functions? Arrow functions make our code more concise, and simplify function scoping and the this keyword. By using arrow functions, we avoid having to type the function keyword, return keyword (it’s implicit in arrow functions), and curly brackets. This keyword in arrow functions A normal function has its this keyword ie the scope of this keyword in normal function is its function. whereas in arrow fnction, fat arrow does not have its this, fat arrow takes this from its parent function Which takes us to a conclusion that you should use fat arrow/arrow function when you want to use this of parent function, in case you want to use this of current block/function you should use normal function. for eg take this eg. //profile is an object const profile = { firstName: '', lastName: '', setName: function(name){ let splitName = function(n){ let nameArray = n.split(' '); this.firstName = nameArray[0]; this.lastName = nameArray[1]; } splitName(name) } } profile.setNmae("vikram sharma); console.log(profile.firstName) this code will not give us any output as "this" keyword in normal function will look for its value in the same function only(which is this) setName: function(name){ let splitName = function(n){ let nameArray = n.split(' '); this.firstName = nameArray[0]; this.lastName = nameArray[1]; } , whereas if we use arrow function const profile = { firstName: '', lastName: '', setName: (name) => { let splitName = (n) => { let nameArray = n.split(' '); this.firstName = nameArray[0]; this.lastName = nameArray[1]; } splitName(name) } } profile.setNmae("vikram sharma); console.log(profile.firstName) This will give the output as vikram, becasue fat arrow automatically sets this keyword to setName ie its parent. 6) What is prototype inheritance? Every object has a property called prototype, by which you can add methods and properties to it and when you create other objects from these objects, the newly created object will automatically inherit the properties of the parent, not by including in its own properties but instead it uses from its parent. The way it works is, when you call a particular object or a method it first looks at its own properties if its there and if its not there it will look in its parents properties, therfore this way objects are much lighter. eg: let car = (model) => {this.model = model} car.prototype.getModel = () => return this.model let toyota = car("toyota") console.log(toyota.getModel()) ie we inherited model property from our method car in another method getModel by protyping car 7) what is the difference between function declaration & function expression? console.log(funcD()) ---> function declaration //ie its available to us even before its declaration console.log(funcE()) ---> error // its saved to a var and will behave like one, moreover it has a variable scope function funcD() { console.log("function declaration") } let funcE = function() { console.log("function expression") } 8) what is promises and why do we use it? We use promises to simplify a callback hell 9) What is setTimeout()? 10) what are closures? When a func returns another func, the returning function will hold its environment "Closures are functions that refer to independent (free) variables. In other words, the function defined in the closure 'remembers' the environment in which it was created let obj = function(){ let i=0; return { setI(k) { i=k; } getI() {return i} }}

I feel like he's feeding my brain fresh organic vegetables. You know what I'm talkin about.

8 out 10 questions were asked in my interview, after listening to your tutorial , i am pretty confident about everything .thank you so much gurujiii, all the best!! great going !!!

Thanks, almost all above questions were asked in my interview and I had no clue about a few of them and I was rejected, your tutorials are too good for the beginners. keep motivating us... thanks a ton.

you are the best vanilla javascript teacher ive seen them all from paid ones to free ones you are the best one if not the top 3

omg, last week I literally got asked all these questions except for the prototypal inheritance and the function declaration vs expression thing. I hate to say that at that time I didn't find your video so I wasn't able to answer what a closure was. And they also gave me a tricky settimeout exercise. Anyways, they asked for a second interview and here I go again! Thanks a lot for the info!

Also would like to add that Promise actually gets queued up in the microtask queue while setTimeout gets queued up in the callback queue. The prioritization of the event loop is that microtask queue -> callback. Therefore if you try to do a setTimeout before a promise ,let say to fetch some API , a promise will actually get returned first.

what is prototypal inheritance? 0:27 what is the difference between function declaration and function expression? 2:57 what is promises and why do we use it? 4:22 setTimeout() 6:42 what is closure and how do use it? 8:22

Just wanted to comment that you CAN pass a declared function in as a variable. You give the function a name in the declaration. So in his example, you'd be able to pass funcD into funcE (if funcE accepts arguments), so something like...funcE(funcD) would console log out both strings (again...if funcE calls the argument passed in)

I've got an interview next week and these videos are solid interview prep gold. Thank you :)

I watched this tutorial after having watched your other tutorials on Closure, Promise, Call-Apply-Bind, and I have to tell you all three questions puzzled me in my latest interview - so thank you again for sharing these nuggets and helping us better understand problems that puzzled us in the first place!

Few of the Questions asked in my Interviews so far. 1. [x,y,z] = "abc"; Console.log([x,y,z]) 2. Why does Javascript have both null and undefined? What was the need to retain undefined? 3. for(var i =0; i

Great videos (both of them), thank you. Having said that, I could spot one mistake. At 4:00 its stated that to pass a function as an argument to another function we would have to use a function expression. This is not true, we can pass a function declaration as well. Also, it is worth mentioning that function declarations are hoisted whilst function expressions are not.

I am learning more with your videos... I gave up reading so many book to learn simple things. Thanks

My first JS interview was fun, ya I didn't do well. But when I was asked those questions, I felt that I knew the answers but not able to answer them. The questions include closures, inheritance and ES... That was fun. And now I am getting into JS stuff ... And these videos are helping me. Thanks :)

I found these tutorials to be VERY helpful and great interview prep.

watched the whole series && learned a lot. thanks!

Awesome video! This is probably the 10th-odd video I've seen of yours and they've always been very clear and easily to follow. Keep up the great work!

Hey Buddy, This is the best javascript channel i have seen who covers the topic which are hands on daily javascript programming and The content of this channel is very helpful for beginners as well as mid senior JS developer who is appearning in JS interviews. I want to say you something that why you dont try some aws and node js advance practices that will be very helpful for the subscribers to understand modern trends. Thanks For all your help!

I think you have the knack for imparting knowledge - I love it! Cheers.

Thank you for your help. I wish I would have seen this before my last interview. I like how clear and concise you are with your explanations but I wish that your microphone was a little bit louder.

I wasn’t aware that Closure was an actual property that can be accessed. Thank you for showing me this!

Aweosme...just love your videos...they are very helpful...

Thanks for posting this video and It's clear and depth ...please provide more videos of Js and Angular

I am a big fan of urs, You explain things in very efficient way, One question "How does JS manage multiple events in parallel, like click, input, etc. when it is interpreted & single threaded?"

Thanks for sharing this video... From these 10 questions, i got 8 questions in my interviews. Please share more questions from javascript and angular.

It is very helpful, I was asked some of the questions already. Thanks!

Great questions! I’d like to suggest switching to a dark theme for your IDE. Watching this on a large display, your editor is just a wall of white light and difficult to read. Thanks for your videos!

Thank you..missed call Bind and Apply in this video..frequently asked and we struggle to answer that..anyhow i checked it in advanced javascript tutorials

Awesome video and explanation (part 1 as well). It really helps me with the interviews! Thank you very much!

Hast's off man, you doing really well job. Also add because I have faced multiple time this quest. "Event Bubbling" & "Event Delegation".

Not sure if this is what he meant at @4:01 but it works fine: function one() { return 1; } function runAndLog(f) { console.log(f()); } runAndLog(one);

my first js interview went terrible as i didn't watched this video but will go for more as it gave me some nice experience

This is a hidden treasure I have found. Very informative and nicely put. you are a gem of a person and I really liked the way you have explained the topics with ease.. kudos and keep up the good work and I’ll look forward to more videos from you.

Thanks for your video! It's very useful. Could you please enable your subtitles caption just as other videos you did before? Thank you so much!

Really clear explanation, Really it helps me to clear my concept

Thanks for this video. Yes, closure is a very important topic of Javascript. I have faced it two times.

Thank you ,this series is great ,please keep building

Thanks for posting this video it is very helpful for beginners....:-)

I really like this guy's videos, seems very real life experience and good examples to illustrate the topic.

Great explaination!! Simple & crisp.. :) Keep going..

I have an interview tomorrow and mostly about javascript. I have a feeling that I will fail it but many thanks that I found and watched your video. Very helpful!!

for a junior dev interview i have been asked what are media queries and how to you code them, == vs ===, and var vs. let vs. const :)

Hats off to your patience. What a great and simple way to explain things. Thanks sir.

Thanks, man, you showed the best example for closures understanding, nice job!

Thanks for the video. The example you used for prototypal inheritance was actually the function definition using prototypes. There is no child parent relation anywhere. Correct me if I am wrong.

@techsith, 4:10, I think you can pass function declaration as an argument, should work. Not sure if I understood you properly, because the following code works, function count(val){ console.log(val); } var t = function(func){ func(5); } t(count); // prints `5` In JavaScript, functions are high order objects.

What do you think the future holds for Angular? I have tried both Angular and React and Angular comes more natural for whatever reason. With this whole patent thing, could we see more people turn to Angular? I know that Vue is the newest and hottest framework right now but still....

Would like to see video on design patterns in JavaScript. And what to know React is based on which design pattern.

excellent explanation on prototypical inheritance! thanks

Love your videos techsith I just subscribed, keep this series going!! please also provide us with data structures/algorithm questions as well.

What are your thoughts on this problem solving process: 1: restate the problem 2: work through an example and test for edge cases 3: think about the implementation (Pseudocode) 4: write the code 5: test the code with correct input and edge cases 6: relax at bar after interview if you think you tanked it.. ;0)

Around 04:10 I'm 99% sure I understand what you're getting at but an example would be really helpful to solidify the explanation

I subscribed, your way of explaining is very good and relaxing

To 4:00 here is example of using function declarations and function statement as a callback to funcktions : jsbin.com/cohozaciwa/edit?js,output

Thanks for the nice tutorial, but I wish the answers were displayed on a slideshow so we could take notes easily.

In last example you returned an obj with 2 functions (setI and getI) that didn't had the function keyword ih their declaration. I honestly thought that wouldn't work! Thanks for the tutorial.

Thanks a lot for feeding us with the Javascript knowledge and preparing for interviews.

v helpful... can i request you to pls do a video on generators that is tied in to a practical use case... a lot of the tutorials on generators seldom go beyond explaining the syntax... thanks again for producing JS content

Hi there I am wondering if we can compare the concept of "promises" in javascript to be similar to "delegates" in C#? Are they the same thing? In C#, Delegates are function pointers which are useful for callbacks and checking the current status of another running function while within one. They allow you to pass methods as objects. I am wondering if the two concepts are similar. Surprisingly I never knew about either of these before these last few months, so I have been trying to use delegates in C# but mostly in toy problems so far. I am struggling to understand practical usage for these despite watching and reading many things.

Just one note: It is considered good practice to name constructor functions with an upper-case first letter.

you are a god techsith... thank you

Awesome tutorial. Thanks

Has the best interview advice from the back of the video.

It is very useful and please provide oops concepts of javascript sir thankyou for helping us in this way

Thanks for the good feedback after the tutorial you gave on interview related . It's really helpful and so does the knowledge you shared through your all videos are helpful for a fresher. Hope you post such quick short important questions on web development in future. Thanks

i got the closure and the promise questions only !.. and it was too hard for me. the others i know . thank you so much. i need to practice es6

You're the first popping up in KZfaq search result! Would be nice to have a better microphone. Cheers

You're so amazing, so clear

Function Declaration type of function can be passed around with proper scopes. I tried this with window scope for now

04:05, it's not true! you can pass declaration as parameter to another function

Thanks a lot, very clear explanations. Could you please make videos on common JS coding challenges given at interviews?

hi! thanks for the lesson & it would be better that u keep your voice in same rhythm, voice going up & down which is hard to hear

Ledies and gentlemens. he is a good teacher. Yesssss??!

Very good video. One can get a positive attitude with it. Great job my friend.

i am big fan of u and thanks for vedeo, please post videos like this. Gain knowledge and confidence at same time. subscribed:)

I think you should make a video explaining about Promises in detail.

Thanks for the video! Very enlightening!

Console.log([] + []) // output: “” Check how array treated internally for explanation

This channel is very helpful. I did not expect it to be this good given that bad meme use for thumbnails.

Sir Great video but please improve the Audio Quality.

Great sir, Why not you start your udemy course till now? And I am the beginner I have started watching your videos 2 days ago. These are unique and strong our fundamental concepts.

You can pass a function declaration as an argument to another function though. function innerF() { console.log('I ran!'); } function outerF(inner) { let a = inner(); } outerF(innerF); // 'I ran!'

By convention, constructor functions meant to be used with new are named with starting Capitals. So I believe it's better to name car at 2:05 as Car

Thanks so much for sharing your knowledge....Awesome !!!

I had faced a complex question. May not say it complex. But I was not able to answer it. that was something like that:- a) '1' + 1 = ? b) '1' + '1' = ? c) 1 - '1' = ? Ans: a)'11' b) '11' c) 0

Well explained...keep posting sir :)

4:10 I'm not sure why you said in the video we can't pass function declaration into another function? If we declare a function we can pass it as an argument to another function.

11:31 life lessons learned from admiral Ackbar.

Great job

at the 4:00 examples difference between function declaration & function expression ; IF you used a VAR instead or a LET for funcE, instead of throwing an error wouldn't it show as a undefined for funcE just like it did for funD?

thanks for this. Really threw me that getter & setter methods don't need 'function' keyword in ES6. might be worth mentioning that.

Recently found your videos. I just subscribed thanks for your help!

Hey Smith, Fantastic video, please increase video volume. Thank you Cheers!

Nice tutorial sir :) Thank you!

your videos are great but please sir its a request next time speak little bit louder, my phone volume is full but some words are not audible.

best explanation for closure

You cannot pass a function declaration to another function, you have to use a function expression.Sir, can you give one example function foo(x) { console.log(x); } var bar = function(func) { func("Hello World!"); } bar(foo); function foo(x) { console.log(x); } var bar = function() { foo('hello world') } bar(); sir its work.