JavaScript Practical Applications of Call, Apply and Bind functions

[@DanielDogeanu]

I was asked exactly this at the interview, today. I had no idea what they did. Now I know. Thanks!

[@Techsithtube]

Its good that you know now. :) You will be prepared for the next interview.

[@bot_matrix]

Thank you sir! Compared to other KZbin instructors, you are calm, collected and make everything easy to digest. You get a like from me!

[@Techsithtube]

Thanks for the very very positive comment. :) Keep on learning!

[@veronicaeulenberg6612]

"Binding outer this to inner this." That's a pretty good explanation for binding this.

[@Techsithtube]

Veronica, thanks for watching!

[@sivakalithasan2818]

Great work and easy to understandable for this video

[@haseebshahid5148]

that = this ---- The classic arrow functions solved that ugly design pattern. great video!

[@juancarlosfigueroa617]

That's the thing i was going to mention with arrow functions you also don't need to use bind since the arrow functions keep the scope open to the father scope

[@javascript_developer]

thank you for the awesome. you make javascript understand very easy.

[@Error_Mode1219]

man you're so underrated subscribed

[@olajumokeboladale-lawal8688]

To turn the argument into an array, we could also do make the argument a spread operator when passing it into the function then convert it into an array by saying: Let arrArgs; Let argsToArray= function(){ return arrArgs=[...arguments]; }; Right? And then calling the function argsToArray(1,2,3) should console[1,2,3]?

[@Techsithtube]

Yep that would work .

[@SKU009]

Must watch video, if anybody want to understand call, bind and apply.

[@Techsithtube]

Thanks for watching!

[@PrajwalCoding]

these are the exact questions being asked in mcq rounds and interviews and bro has done these videos 6 years back :))

[@javascript_developer]

Its very clear for call and apply. For bind I am very confused. Will do more exercise.

[@Techsithtube]

think of call and apply as renting tempararily . And bind is more like making it own.

[@ManontheBroadcast]

Could we also use Array.from() to turn the arguments object into an array? ...

[@Techsithtube]

yes that should also give the same result.

[@fatimahal-khateeb4627]

why click loosely bounded to new object? 10:56

[@sirishaepari8938]

@techsith Could also help us clear the difference between call, apply, bind vs prototype vs __proto__ ? As a developer, when/how should you use what?

[@shivangjoshi4233]

You can do Math.min(...numArray); to get same results as apply method

[@SoccerChannelviews]

great sir! keep going, this the real thing... supporting you till you get success, just keep making these awesome videos up

[@Techsithtube]

Thanks for all the support and thanks for watching! :)

[@Welcometomyjourney20]

Very helpful. Thanks. I think instead of using call/apply, better & shorter now to use es6 spread operator, to copy functionality from obj to obj. Commonly used in react now. Example: function doSomething (x,y,z){ } let args = [a,b,c] doSomething(...args)

[@srihitha4721]

Sir, I have a same scenario, and want to unit test lion class. Problem is cat calls a function of mamal which returns a promise. How do I unit test this scenario from lion class.

[@yuvisaran]

Great and simple explanation thank you so much

[@Techsithtube]

Thanks for watching Yuvisaran.

[@miroslavspirkoski5623]

Thanks for these amazing Javascript series, these series are a real lifesaver!

[@binayakgshankar9188]

Watched more than 10 videos on the same, but this one cleared my concepts

[@Techsithtube]

Binayak, I am gald that you got the concept. Thanks for watching! :)

[@ruchirai5775]

At 13.54 I can even use arrow function to get this context ? We don't need to use bind isn't it ?

[@Techsithtube]

Yes ruchi, you can use arrow function there.

[@aumgnfeig9367]

How are you defining "that" in the render function without using var, let or const?

[@patrickdooley4031]

Thanks TechSith. Great Explanation!

[@dhimanchakraborty5639]

Sir, one confusion I have. When I am declaring a function like const fn = function(something) {} and call it with an object, javascript call function works, but when I try the same with arrow functions like const fn = something => {}, it doesn't work. I tried to print "this" in console with console.dir(this), and I got the object and window object for the two cases respectively. Please let me know why this thing is happening? Sir, your videos cleared many painful areas in JavaScript. Thank you so much.

[@soumitragiri1353]

all the concept is going to clear, but where should i will be use bind(). for me , bind has not clear. could you please elborate why new button object is loosely couple bonding with prototype?

[@aswebdev]

Is it correct to say that the spread operator (...) has reduced a lot of the complexity that was brought about by call/apply/bind ? For e.g. We can do min like this using spread operator in es6 :- Math.min(...numArray);

[@Techsithtube]

yep, spread operators have some really good use. and it has simplify lots of complex things.

[@dheerpandey]

Hi Techsith, I am getting "add clicked", when I calling "newButton.click();", how it is different from let looseClick = newButton.click; looseClick(); Running above code in chrome, also when I am executing the code in node console, getting exception i.e. => TypeError: Cannot read property 'content' of undefined. Why this is happening, please clarify.

[@Techsithtube]

looseClick is not part of the object anymore and not bound to the button so it wont work . And newButton.click() is part of the object . I am not sure why its not working in node. Try to debug in node.

[@joseigor8556]

Sir, your tutorials are amazing!

[@pratikfulkar4335]

great work

[@aditibhatia100]

Amazing video, clears all the doubts in a very simple manner

[@vincesanchez7790]

Great tutorial

[@Techsithtube]

Thank you! Cheers!

[@saransh9306]

You said we can use call/apply when we want to borrow functionality from another objects...But Why would you use call or apply to borrow functionality from other objects when you can just simply do obj.FunctionName() inside another object to borrow functionality from other object? Example: var obj = new function(){ this.prop = 'inside obj'; this.Add = function(a,b) {return a+b}; this.getinfo = function(){console.log('inside getinfo of obj object')}; } var anotherObject = new function(){ this.getaddition = function(a,b){ return obj.Add(a,b) }; //borrowed functonality from obj without using bind. } what would be the use case in above example where using call/apply/bind is a must ??

[@Techsithtube]

in your example the function that you are tying to call doesnt have 'this' so it would work . if you want to use one objects method on another object you have to call the new objects 'this' ..

[@saransh9306]

Thank you for clearing the doubt here..

[@frizm1543]

Any idea why the first apply example doesn't work with arrow functions?

[@kenosytb]

Why when you call the mammal constructor you use this and legs and not only legs????????

[@nagaprasad681]

you big bro your tutorials are rocking !! Respect !!

[@madhanj5036]

With New ES 6 feature, to find out the Minimum value from array use REST operator let myarr= [1,2,3]; console.log(Math.min(...myarr)); Its just FYI for all

[@rampande5830]

thank you for sharing valuable knowledge.

[@vinodbhatt3789]

Very useful..

[@igorcweb]

This is gold!

[@2002utube]

I am not sure where I am in my JavaScript learning journey..suppose I practiced all these 52 Videos of advanced JavaScript and thoroughly understood the concepts all these 52 Videos where do I stand in my JavaScript journey...what should I do further to reinforce my learning of JavaScript so as to reach to an expert level?

[@Techsithtube]

I would suggest using those concepts after learning them . Either create your own tiny JS library. or use react where you can use your JS experience. With JS if you don't use it you lose it.

[@soumyaranjanpanda7532]

Helpful video

[@believelody5531]

About "bind", in myObj object I did render() { this.asyncGet(this.parse); } and it works. So why using bind? Thanks for your great tutorial

[@Techsithtube]

what is asyncGet?

[@vickyjain7110]

Please try to provide links to which u refer in ur video... In this video u said u ll provide template string tutorial link 10:23 .. which u haven't provided.. Thanks

[@maskman4821]

what do you mean by translate your video to other language? like I translate what you said in this video to chinese and send to you, and you will put chinese subtitle as an option in the video???

[@Techsithtube]

I am not sure for how to do it for Chinese but youtube provides a link for translation of each video . here is a link for this video. kzbin.info_video?ref=share&v=AYVYxezrMWA

[@hemalpatel19]

Very nicely explained!

[@Techsithtube]

Thanks for watching!

[@prerakdoshi3509]

Very Helpful. Thank you Sir

[@Techsithtube]

Thanks for watching!

[@otaviomota6122]

i spend 1 hour to realize that these functions don't work using arrow function. Or i did wrong ? Do you have any tips that helps me to know when use i have to use arrow function and "normal function" ?

[@Techsithtube]

think of arrow functions pure functions that don't have its own this. so if you want to use this inside your function, don't use arrow function. I have a video on arrow function where I explain it.

[@kakmca]

Nearly 3 years before I saw his video related to Angular Testing. I was so impressed, I liked his teaching very much. I became his fan. After 3 years, today I found this video of him. Sorry sir, but this comment's targeted to you. You please speak with your slang sir, don't try to create new slang.

[@riccarrasquilla379]

good tips. thx

[@ajoco99]

Nice tuto.thanks

[@RethinkingUI]

worth watching it .

[@kavind8938]

But Dude the below code works fine.. Is this because i am not using "let" .. can u explain plz var test=function (name){ this.name=name; } test.prototype.click=function(){ console.log("===>"+this.name+" clicked"); } var b=new test('tesing'); b.click();

[@Techsithtube]

there shouldnt be any problem with let etither. the example you sent would work in any case . now you can do this and see if it works. this were you have to rebind the method back to the object. var test=function (name){ this.name=name; } test.prototype.click=function(){ console.log("===>"+this.name+" clicked"); } var b=new test('tesing'); var bc = b.click; bc();

[@kavind8938]

Practical Applications for PROMISE plzzzz

[@jainshilpi3]

I am not that much clear with call,for call we are passing obj n value I donot understand this line mammal.call(this,legs) could u pls explain?

[@Techsithtube]

mammal is a constructor but also a function that sets some property with this.legs = legs; and when you call from another function mammal.call(this,legs) which means you are calling mammal function on using this of which ever function calling it from. for more info on that you can refer to this playlist kzbin.info/aero/PL7pEw9n3GkoW0ceMeoycg9D00YjPAbtvt

[@nafeesahmed4942]

I was hoping you will continue with angular 4.0,

[@Techsithtube]

I am still continuing with Angular tutorials . I will also release on other topics as well.

[@saransh9306]

didn't get how legs property became part of cat by calling mammal.call(this,legs) ? can you please explain the logic behind it?

[@Techsithtube]

mammal is a function that does "this.legs = legs" so if i call it inside the cat. its like cat.legs = legs. becase 'this' inside cat is actually cat. make sense?.

[@saransh9306]

Yes it does make sense..Thank you:)

[@osazemeusen1091]

This is better than any paid tutorial I have gone through. Thanks why didn't you pass the "this" keyword into [].slice.call(arguments)? Observation: Math.min(...numArray) could also be substituted inplace of Math.min.apply(null, numArray)

[@Techsithtube]

[].slice.call(arguments) just slices the argument object to an array. so there is not need to pass 'this' here.

[@hkn1853]

excellent video god bless you

[@jsnode2075]

is there any upcoming React Series?

[@Techsithtube]

yes, I am going to start releasing by next week. Let me know if you have specific topics that you want to me to cover. Thanks for watching!

[@GabrielVasile]

Easier in ES6 with the spread/rest operator function argsToArray(...args) { console.log(args); } and Math.min(...numArray)

[@dmytro891]

Great video, thank you!

[@phanindrakumarpulletikurti]

Do you stopped angular4

[@Techsithtube]

I am still continuing with Angular tutorials . I will also release on other topics as well.

[@phanindrakumarpulletikurti]

techsith ok

[@seolead5826]

At 7:03 you had me laugh, great examples thanks

[@Techsithtube]

I am glad that you found it funny. thanks for watching! :)

[@AkhiVlogsandtalks]

Hi sir , I want to translate into Telugu ,pls provide the link

[@TropicalTaquito]

I’m trying to understand bind but I still don’t get it :l

[@sergeymigel4680]

thank you

[@taruchumccullough9045]

Thank you !!

[@abinayahui1905]

Great

[@mr.techno-era7474]

@3:55 Javascript - weird language

[@sushmithareddy4722]

Very difficult to understand. Please maybe make another video.

[@elfpimp1]

Hehehe, I keep refactoring your functions to fat arrow as you type them unless they're not refactorable!! :0)

[@kiransahu157]

Please don't use reserved key words for variable or function

[@Techsithtube]

I wonder which reserve keyword I used?

[@kiransahu157]

​@@Techsithtube you are doing a great job, Sir. Started watching all of your JS videos. All are awesome. But while understanding, getting confusions like button.prototype.'click ', after few min, I realize 'click ' is just a prototype property of the button. But i'm ok now. Thanks for the response. :p

[@elfpimp1]

Btw, subbed!

[@PierreSoubourou]

It's hard for me to perceive real world usage each time

[@Techsithtube]

It is hard often times to times visualize application of such concepts. But, its heavely used in large projects.

[@rikilamadrid]

Honest question, why in most of the videos your sentences are cut off?

[@Techsithtube]

I try to cut the dead space between sentences. and unfortunately the editor i am using to do that doesn't have the refined tool so its usually half a second off .

[@Atif1702]

Who the hell are dislikers? what the heck you want more?

[@abhayagarwal5097]

After 5mins I felt like I was lost in desert , didn't understand this cat example at all😑

[@greensmarketingsolutions5]

Bind is so confusing

[@idontknownoori500]

Stop comming in my youtube 😵

[@MainDol1]

Very nicely explained!

[@Techsithtube]

Thanks for watching! :)