Javascript Coding Interview Questions | Advanced Javascript Interview Questions

Learn 5 must know javascript coding interview questions. This are advanced javascript interview questions that I've got on all interviews during the last 10 years. Don't go to javascript interview without learning this things first.

FOLLOW ME

REFERENCES

RECOMMENDED VIDEOS

STUFF I USE

Disclosures: All opinions are my own. Sponsors are acknowledged. Some links in the description are affiliate links that if you click on one of the product links, I’ll receive a commission at no additional cost to you. As an Amazon Associate I earn a small commission from qualifying purchases.

[bogujang]

Please mark missleading explanation at 11:42 as it might confuse others. Return is missing.

Also interesting to mention if you have regular object (not an instance of a class), you actually get undefined with arrow func:

var a = {
prop: 'hi',
a1: () => this.prop,
a2: function () {return this.prop}
}

a.a1() // undefined

a.a2() // 'hi'

[anasouardini]

This works just fine (prints "lll"), because I didn't forget `return`:
class p {
constructor (name){
this.name = name;
}
b = function(){
return this.name
}
}

const c = new p('lll')
console.log(c.b())

[petarstaynov]

Your example for the context and this is wrong. The normal function returns undefined because you don't return anything from the function. The arrow function returns the pet name because you've written it in a way in which it returns this.name.

[johnacsyen]

@11:45, the function version did not have return, which is why is logs to undefined. if return is added to line 9, it also returns 'Fluffy'

[antoniozach]

Excellent video! That channel worth more boost! Keep going well man!

[CANIHAZURDREAMSPLS]

I finally know why we need to bind(this) for class components... because otherwise "this" is global context rather than parent context - thank you sir!

[cjmaaz]

You explained Closures with one more js topic I was asked in an interview "Currying". I guess this is a bonus hidden tip for this video. 😛

[pgn]

THRE IS A MASSIVE BUG in 10:17 example. Line 7 misses "return" and only this is why line 16 logs 'undefined' to the console!!!

[miggu]

it's very hard to do a video like this, thank you. I think functions should be explained in hoisting as they can be invoked before declaring, I know it's one of those js quirks

[victortochila]

You have an error explaining the difference between arrow and plain function:
First of all, you used classes, which is really bad for explaining diff between arrow vs regular functions.
If I add following code to jsfiddle/codesandbox I am getting compiler errors => we should use only methods inside classes.
But anyway your getSurname method returns nothing, so undefined is the only value you could get.
If you return this you would get object here, this is some weird behavior of classes which is not obvious again.

And generally, after your example, it seems like we need to use arrowFunctions for object methods, when the reality is opposite:
We need to use arrow functions almost everywhere where we want to save current context e.g. callbacks, but for object methods, where we need to use regular functions.

[devilslide]

Regarding class example and „this” binding. You are not returning anything from getSurname function. That is why I think you are getting undefined. If you console log “this” for both functions you should get class context.

[kumailn]

you missed the return keyword in function