Javascript Closure Tutorial | Closures Explained

[@DaveGrayTeachesCode]

Closure is often confused with Lexical Scope. Lexical Scope is an important part of closure, but it is not closure by itself. This tutorial provides several examples that should allow you to distinguish between lexical scope and closure. This tutorial should also allow you to learn how to give examples of closure if you are asked during the interview process. It is important to understand scope when we discuss closure. If you need to learn more about scope, check out my scope tutorial here: kzbin.info/www/bejne/lXacZ4psntt7pMk

[@siya.abc123]

Thank you Dave ❤️

[@renatoscraft]

Thank you for another great video Dave!

[@DaveGrayTeachesCode]

@@renatoscraft you're welcome! 🙏

[@DaveGrayTeachesCode]

@Abhijit Desaithank you! That's a great request 💯 I like that idea.

[@Krisler12]

Hi! Supposing you have some secret JavaScript functions that you don't want anyone to know. Also, that code (functions) are very resource consuming and this is why they need to be client side and not server side so you can't write those functions in python or php. Also, obfuscation of JavaScript is not useful since it can be easily deobfuscated or seen by placing a breakpoint in the debugging tools in the browser. This been said, could you make, please, a tutorial teaching us the best way to protect your secret JavaScript functions without paying for third party services? Thank you so much in advance!

[@ukaszpospiech3817]

Out of all the yt tutorials on closures I've watched today, this one's been by far the best. Clearly explained step-by-step with readable code as illustration. Calm voice, proper English pronunciation and slow pace of speaking matter particularly to beginners like me. Unlike most teacher-coders on yt, you're actually capable of teaching. Thank you, good job, I'm going to watch more of your tutorials.

[@DaveGrayTeachesCode]

Glad I could help, and thank you! 🙏💯

[@binadarabzand2701]

Thank you, Dave! An extremely complex concept was explained clearly. Finally, I understood what closure is and how to use it in my code. The IIFE was a cherry on top. Thank you again.

[@DaveGrayTeachesCode]

Glad to hear it and you're welcome! 💯

[@BigSmoke-r9w]

Dave grey taught me html and css! Now he's teaching me one of the javascript topics I find hard to understand! I love this guy, he's the best!!

[@adventurer2395]

You have a laid back, natural, and clear way of explaining things. Much appreciated!

[@DaveGrayTeachesCode]

Thank you for the kind words! 🙏🙏

[@jim_andrus6466]

I can't tell you how much I appreciate the pace of your speaking voice when explaining these concepts. So many of these youtube videos, the person is talking insanely fast, and I cannot keep up with all of it.

[@DaveGrayTeachesCode]

I'm glad it helps! 💯 If anyone wants it faster, KZbin lets them speed it up 😀

[@nirmalshah9947]

This is the first video I've come across, so far, that really goes deep into clearly explaining that simply having an inner function and logging its parents' variables isn't a closure but a lexical scope. Brilliant!

[@DaveGrayTeachesCode]

Glad it was helpful!

[@aya2222]

I spent the whole day looking up videos to understand closure, and finally I could find the best one. Thank you so much.

[@DaveGrayTeachesCode]

Thank you so much for the kind words! 🙏💯

[@SaketK11]

I has started learning web dev from your html videos ...last april .. thanx for teaching us and making begginer understand the relevant topics....

[@captainalpha4853]

You explained closures in a way that even a primary school student will understand. You definitely deserve a sub. Thank You so much, Dave!

[@DaveGrayTeachesCode]

You're welcome!

[@jennisonb37]

I discovered you today, Dave and I am highly impressed with your teaching style. Unlike many other YT videos that teach all this stuff, I can actually understand you. (So many are hard to follow due to the thick accent of the instructor.) I'm looking forward to delving into other videos you have. Thank you!

[@DMT9023]

You've earned yourself a subscriber with this video, your examples and they way you explain things clearly has helped me grasp this concept. After watching about 10 videos and reading numerous blog posts, I was really struggling to visualise what was going on. The next time I get stuck I'll be referring to your channel . Thanks Dave.

[@m-ok-6379]

I was writing closure example after example without really understanding the reason behind it and this video with credit example finally got the closure idea to click. Thank You.

[@DaveGrayTeachesCode]

Glad to hear it helped!

[@khaledbenshible2657]

I spent the whole day looking up videos to understand closure. finally i git it so Thank you so much for clearly and simply explaining

[@ichiroutakashima4503]

The majority of videos made by other content educational creators across various websites talk like they're rappers, you sir are different. Things went much clearer after this video and made me realize that the majority of my confusion is because most of my searches were actually lexical scopes and not closures. I really am indebted to you.

[@DaveGrayTeachesCode]

You're welcome!

[@SC-bv6kx]

Just learned closure several days ago. This video definitely helped me review the concept. It also helped me clear up the confusion about lexical scope. Thanks Dave!

[@DaveGrayTeachesCode]

You're welcome! 💯

[@dileepbc5901]

this is an underrated tutorial, i had to got to the bottom of the page on the youtube to get this video. these explanations & examples are more than enough to understand what closure is.

[@DaveGrayTeachesCode]

Glad it helped!

[@stavroskefaleas6320]

Best video tutorial on javascript closures on the whole internet. Period!

[@DaveGrayTeachesCode]

Thank you!

[@MasPensador]

Finally I fully understood closure.... thank you and bless you

[@hongzhonghu6364]

The best and detailed "Closure" explanation on the internet

[@DaveGrayTeachesCode]

Thank you! 🙏🚀

[@toyosisalami6453]

Before coming across your video I had already watched three other ones that weren't explanatory enough for me. Thank you so much for this video; I got everything. Thank you.

[@DaveGrayTeachesCode]

You're welcome! 💯

[@joro353]

This is by far the best tutorial on closures I've watched. Thank you!

[@DaveGrayTeachesCode]

Glad it was helpful!

[@mertasilturk8400]

i watched too many closure videos but first time i understand clearly . thank you so much

[@DaveGrayTeachesCode]

Glad it helped! 💯

[@TusharBorawake]

This is what closure is...I was just thinking lexical scope is closure. Superbly explained. Thanks alot.

[@DaveGrayTeachesCode]

You are welcome, Tushar! 🙏

[@proactivex]

I watched maybe 10 videos on closure. Finally one person can explain it well, Dave Gray! You also crushed on that song white ladder.

[@DaveGrayTeachesCode]

Ha! I do share my name with a few others, but I'm glad I could help with closures! 💯🚀

[@connectyonas2149]

I really found this explanation about lexical scope and closure the best one from KZbin. Thank you.

[@DaveGrayTeachesCode]

Glad it was helpful! 💯

[@slowcoding]

감사합니다.

[@DaveGrayTeachesCode]

Thank you for the support! 🙏

[@dopetag]

The best teacher to explain advanced concepts of Javascript. Instant subscription!

[@DaveGrayTeachesCode]

Welcome aboard! 💯🚀

[@MB-hn5qk]

Probably the best Closures video I have ever watched. Thanks!!

[@DaveGrayTeachesCode]

Glad you liked it!

[@arescatalin1407]

I have smashed that like button and I hope that this playlist keeps growing as these concepts really make a difference. Thank you for sharing your knowledge with us

[@DaveGrayTeachesCode]

You're welcome! Glad I could help 💯

[@szangyi24]

Dave, thank you so much for this tutorial. I finally got my "Gotchaa!" moment about closures. I watched several explanations before but this really helped me to understand. Lifesaver :)

[@DaveGrayTeachesCode]

Glad it helped!

[@harvard004]

12:45 The important highlight he mentions. IIFE code happens once. The anonymous function inside it only get's returned ONE time (to privateCounter). After that, you can look at privateCounter as: privateCounter = () => { count +=1; console.log(count) } //but with it's own access to private variable "count". -I'm guessing you can say it has enClosed it's scope over the function and it's declared variables. 5:45

[@wzup23]

Thanks dude, it's so clear. I will definitely rewatch this over and over again until I am very familiar with the concept.

[@yogeshkhatri4555]

People misunderstand js a lot. People like u make it relevant for us js peeps. Keep going!

[@DaveGrayTeachesCode]

Thank you!

[@johnmcaulay4348]

Thanks man, I've been struggling with this for days! This video finally made me understand closures (it gave me the aha! moment). I liked the way your video went beyond the cliche closure examples which weren't allowing me to actually understand practical uses for closures. Subscribed!

[@DaveGrayTeachesCode]

Thanks again, John - check out my tutorials on debounce, throttle, and memoize to see closures put to good use, too. 🚀

[@estherokiki5894]

Thanks for all you do, Dave. Your videos are the best. I've watched several videos on closures, but none of them explained it better than you did. I finally understand closures!

[@DaveGrayTeachesCode]

Awesome, thank you!

[@abdelbasset8280]

Thanks Dave you could help me to understand the most confusing concept in js, after I read a lot of articles and watched a ton of tutorials.

[@DaveGrayTeachesCode]

You're welcome! Glad I could help. 💯

[@DLeRoux]

Dave, you need to seriously consider putting together a Javascript course with projects for Udemy. Your explanations are crystal clear. I have found myself doing course after course, stopping, and then trying to find someone else who would be able to explain the concept a bit clearer than the instructor. It wastes a lot of time. I have found myself coming here for the past three or so concepts, and they click straight away. So thank you.

[@DaveGrayTeachesCode]

Thank you, Darryl! I do hope to put a premium course together sometime later this year. I am not sure if Udemy is where I will launch it though.

[@umairyatoo8490]

Thank you very much, Dave. You explained it in a very beautiful way possible. You know I had been struggling from this since long. There wasn't any such explanation on the internet! Thanks a lot.

[@DaveGrayTeachesCode]

You're welcome, Umair 🙏

[@je3043]

Just a quick thought. I think the "credits =- 1" line should be at the end of the function since we need to check credits' amount first to evaluate the possibility of playing. In the example we should be able to play 3 times and it only allows two plays. Everything aside, great video and I always find your explanations very helpful!

[@imperativeemarketing5546]

I "Thumbs Upped" your video. I've been studying JS recently for a few months, and to my surprise everything is getting easier to understand, like I'm on the steeper part of the learning curve. I've been getting a clearer picture of what closures are, but your explanation helped even more to demystify closures to me. You have a very sensible, logically explanatory and intelligent way of explaining closures. I'll be checking out your other videos because I like your teaching style. Who knows, maybe I'll buy you a cup of coffee :).

[@DaveGrayTeachesCode]

Thank you for the kind words 🙏💯

[@youmnaification]

This is by far the best explanation of JS closure. Thank you Dave. I'm glad I came across your channel.

[@DaveGrayTeachesCode]

Glad it was helpful!

[@wallacepei4529]

Thank you for clarifying IIFE, it's syntax that has been tripping me up and now I understand what it's doing. Excellent demonstrations for closures.

[@DaveGrayTeachesCode]

Thank you, Wallace. 🙏

[@RandyHawkinsMD]

Clear, simple, concise, well spoken and very useful. I followed along with your code in my IDE (Velo) with no difficulty. Thank you.

[@DaveGrayTeachesCode]

Great to hear!

[@oscargm1979]

Perfectly perfectly and perfectly explained. Congrats

[@shadabs000]

Finally , finally I could wrap my head around this concept. It's so basic and easy.

[@DaveGrayTeachesCode]

Glad I could help! 💯

[@georgesword2012]

Your tutorials are simply the best on KZbin, thanks for your effort you put for creation high quality content for free ! ❤

[@stephaniezun]

Thank you so much for clearly and simply explaining this concept!

[@DaveGrayTeachesCode]

You're welcome, Stephanie!

[@kumarisuman4565]

This was a great video. I was struggling with closures for some days but now I feel like i understand it now. THANKS Again it was a great video.

[@DaveGrayTeachesCode]

Thank you, Kumari. Glad I could help!

[@bethcarretta5715]

I wish I had stumbled across your video sooner! I've been trying to wrap my brain around closures for so long. Super helpful! You got a new subscriber!

[@DaveGrayTeachesCode]

Thank you, Beth!

[@renras1057]

Best video about closure so far. You are a very good teacher.

[@DaveGrayTeachesCode]

Thank you, Ren! 🙏

[@mno7x]

Thank you for your video! This is the most understandable explanation of closures I've seen and has solidified my understanding of the concept. Really appreciate the emphasis on what "lexical scope" is and how it's an integral part of -- but not the whole story with -- closures. Truly awesome! Thank you, good sir!

[@mi5956]

Thank you for clear examples, I finally understood. I looked at other youtubers and it was confusing.

[@DaveGrayTeachesCode]

Glad it was helpful! 💯

[@zm690]

This is the best closure explanation for me... Great work.

[@DaveGrayTeachesCode]

Glad it was helpful! 💯🚀

[@Albert_Hall]

Great! Great! Great! Thank you very much! Very good explanation! Very good examples!

[@DaveGrayTeachesCode]

You are welcome!

[@pharmakidsarl8449]

One of the best video on closure

[@kalyann3426]

It’s so refreshing to listen,well explained.Thank you Dave

[@DaveGrayTeachesCode]

You are very welcome

[@tanzimchowdhury320]

Thank you Dave, you just got a new subscriber

[@abhinavtiwari89]

This is the best tutorial on Closures. Thank You!

[@DaveGrayTeachesCode]

Glad it was helpful!

[@a5tr00]

Finally I understood JS closures! Subscribed!

[@DaveGrayTeachesCode]

Glad to hear that!

[@sugarfairy1248]

well chosen examples demonstring the unique characteristics of closure. Finally undertand it now!

[@bluevojka]

This was Amazing Dave!!

[@leoMC4384]

I've been programming on JavaScript for over 2 years, I hope I'll feel ready to apply for a job soon, even being old to start, I'm 36. Until now, if I was asked about Closure I replied about lexical scope. The IIFE explanation was interesting although I knew it already, because I used them on my API. I do full stack with MERN. Anyway, great video, very clear explanation. 👏👏👏

[@DaveGrayTeachesCode]

Thank you, Leonardo 🙏 You're never too old to do what you love - keep making progress! 💯

[@erfanfarhadi]

your last example was lovely , thank you

[@DaveGrayTeachesCode]

Glad you liked it!

[@shivashankar6043]

Thanks Dave for this video, please continue the advanced js playlist. You explaining hard concepts easy to understand.

[@DaveGrayTeachesCode]

You're welcome, Shiva! I do plan to do more 🚀🙏

[@NadaAlSharqawy]

This is the only explanation that made me understand it, thank you

[@kostiantynkarzhanov9216]

Dave, thank you so much for your tutorials! All of them are very well structured and easy to understand. I really appreciate all the work you do. Thanks again. Awesome channel! 💛

[@DaveGrayTeachesCode]

You're welcome!

[@hackmeornot2196]

this man, helps me to understand closure quickly and easily!

[@DaveGrayTeachesCode]

Glad to hear it! 🚀

[@alimohammad-lg8sw]

Thank you so muchhhh The best closure explanation ever

[@gopishivakrishna9707]

Not bored at all. Nicely presented. :)

[@DaveGrayTeachesCode]

Thank you! 🙏

[@gerar10s]

Great video! This explains a lot and you've got a new subscriber. It might be my lack of Javascript knowledge but I still don't quite understand why after the first time, every time the parent function is called, only the child function executes and not the WHOLE parent function. I'm going to watch it a few more times and see if it sinks in. Thanks for the video!

[@DaveGrayTeachesCode]

Glad it was helpful! This explanation may help... The parent function is only called once. It returns the "child" function. The variable is therefore set to the child function that is returned. Afterwards, using the variable, only the child function is called. The closure allows the child function to still access the variable that was created within the parent. What we're really referring to here is the lexical scope of the function that is returned, but using the parent and child terminology could help! 😀🚀

[@ARandomPerson--]

Wow that quick explanation really helped. Thx

[@GrahamO-g5g]

Best explaination on the web. Great job sir! Thank you!

[@GeorgiosAmsterdam]

finally found a video about closures that makes sense. Thanks

[@DaveGrayTeachesCode]

Glad it helped!

[@alexandra.thegreat]

Excellent explanation, thank very much for this video!

[@chetanjain4616]

just found out about this series! Loving them

[@DaveGrayTeachesCode]

Thank you, Chetan! Glad you like it! 💯

[@antonchigurh4125]

This was a masterclass on how to explain abstract concepts with easy-to-follow, real-world examples. Thank you. Subbed!

[@DaveGrayTeachesCode]

Awesome, thank you!

[@mohamadybr]

This tutorial is so well structured it simplified the closure concept in a brilliant way!! Thanks a lot

[@DaveGrayTeachesCode]

You're welcome! 💯

[@InnaKasyan-f8h]

Thank you ! The explanation is extremely clear for beginners.

[@DaveGrayTeachesCode]

Glad it was helpful! And you're welcome! 💯

[@practicalandplannedhomeschool]

This video was an instant subscribe. It was well thought out and clear, and I now understand two concepts much better than ever before. Closure kind of blew my mind. Thank you so much for sharing your knowledge!

[@DaveGrayTeachesCode]

Welcome aboard! And glad it was helpful!

[@josephochoa1269]

Hey Dave! is it possible to say that the example at 3:40 IS an example of a closure, but perhaps an example of a POINTLESS closure. And then the continuing examples are simply showing the benefits of a closure?

[@DaveGrayTeachesCode]

All of the examples in this tutorial exist to give simple examples and understanding of closure. I do have some more advanced JS tutorials showing practical applications of closures. Look at the videos I have for memoization, debounce, and throttle as a few examples of closures practically applied.

[@maxralph01]

Awesome. Pretty common concept coming from Laravel, PHP (we call it "a function called from another function"). That made me familiar to the concept beforehand. But I was lost on the application in JavaScript. Amazing, top-notch explanation, Dave! Now, I can use it in JS.

[@DaveGrayTeachesCode]

Glad you liked it!

[@srinivasaraoyp3640]

In the beginning, I found it difficult to understand the topic "closures" it is so confusing. After watching your video demo, I understood it. Thank you very much Dave.

[@DaveGrayTeachesCode]

Glad it was helpful! 💯

[@joynal_dev]

Your videos are absolute gems 💎. Keep up the good work.

[@DaveGrayTeachesCode]

Thank you! 🙏

[@manochpriyankara6379]

wow...Great explanation...Thank you, Dave...

[@gamewidge]

Hi DaveGray, I’m a student and have completed learning the MERN stack from your channel. I would love to see a course focused on building microservices with serverless architecture. It would be great if you could cover topics like designing, deploying, and scaling microservices using platforms such as AWS Lambda please.

[@romanr5962]

Brilliant explanation IIFE , my friend.Thanks

[@DaveGrayTeachesCode]

Glad it was helpful! 💯

[@SuperDarmino]

Replayed this video several times. I think i now get it finally 😂. W3 definition makes alot of sense now.

[@DaveGrayTeachesCode]

Right on! 🚀

[@AR7editing]

Thank you, I really thought that I know closures, but I was completely wrong, nice video

[@DaveGrayTeachesCode]

Happy to help!

[@ikurbano]

thank you, Dave! as always, easy to understand, yet consise and to the point.

[@DaveGrayTeachesCode]

Glad it was helpful! 🚀

[@ToddPressleyy]

Really loved the ball field analogy! At times I’ve struggled to explain the concept of closures to teammates. this will help greatly… thanks for the great content!

[@DaveGrayTeachesCode]

Glad it was helpful!

[@jiweihe3413]

Thank you! Finally understood this important concept.

[@DaveGrayTeachesCode]

Glad I could help!

[@ibnulferdous]

You made closure clear to me! Thank you so much!

[@DaveGrayTeachesCode]

Glad it helped!

[@mikegogl]

How did I now know about this channel before. Thank you.

[@DaveGrayTeachesCode]

You're welcome!

[@lttaylor2892]

Hello Dave. In your explanation of IIFE, At approximately 3:59, when you are explaining that the console.log returns only once, you stated that the console.log only returns once. Could you explain why (when you call this function for the second and third times) doesn't the console.log occur for the second and third time?

[@DaveGrayTeachesCode]

This is a video about closure. I do not see what you are referring to at 3:59. Are you asking about the IIFE video here instead of the comments of the IIFE video?

[@kenluong1838]

Hello Dave. Your contents are tremendously helpful to me as a self-directed learner of frontend dev. You've got yourself a new subscriber :). Your explanation of JS closure is crystal clear but I still have a burning question which I hope your could provide clarification. I am tempted to say the reason that nested function still have access to outer function's variable, even after outer function has returned, is that garbage collection can't destroy these variable. They are still referenced by a nested function. In other words, these variables are still present even though the scope in which they were created is not. Thanks again for your time and efforts!

[@DaveGrayTeachesCode]

You're welcome! Good comment, too. I believe you can say the lexical scope of the function still exists because the function exists. 🚀💯

[@kenluong5081]

Concisely put!

[@siya.abc123]

This is it, this is the video of you want to understand js closures! Thanks man

[@DaveGrayTeachesCode]

You're welcome!

[@soumadip_banerjee]

Thank you Mr.Gray 🤍

[@DaveGrayTeachesCode]

You're very welcome! 💯

[@joannbarney7210]

Excellent explanation of closure. Thank you!

[@DaveGrayTeachesCode]

You're very welcome! 💯

[@aikmo]

You are the best one that explained it. Thank you a lot.

[@DaveGrayTeachesCode]

You are welcome!

[@DheerajKumar-di1cv]

Thank you, Dave! It's really a complex thing to understand, till date I was confused between lexical scope and Closures. But It's all cleared now :) God bless you

[@DaveGrayTeachesCode]

You're very welcome, Dheeraj! 🙏🙏