Don't Imitate, Understand #2 - Promises, Async, and Await

Let's get a proper mental model of Promises, Async, and Await in JavaScript.
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[@sabirnawaz1304]

Wow hearing that soul full voice after a lot of time is like a blessing to my ears

[@TonyAlicea]

Thank you Sabir!

[@YisName]

@@TonyAlicea Tony I’m glad to see you are posting. Thank you very much for all of your hard work! Why you inactive everywhere? I start thinking something happened.

[@Martin958]

@@TonyAlicea Is there any chance you can more courses like your Javascript course? Except for other things like Bootstrap, CSS+HTML and other things?

[@shofada]

I actually "liked" the video before watching it from the beginning till the end. I guess this is called Trust!

[@General_Aladeen]

same

[@YoloMonstaaa]

I wonder if it lived up to the *promise* 🙈

[@fernandafernandes5200]

Same here! Tony is the best!

[@nerdiloo9863]

ditto lol

[@user-og9nl5mt1b]

Never trust anyone blindly

[@ballenf]

This video should be required watching of every full stack dev starting out.

[@ramirovaldes4889]

You mad genius. After dozens of videos, I finally found one that actually explains what is going on. Thank you so much.

[@TonyAlicea]

Thanks Ramiro!

[@user-zb5jp4ti1d]

Guess who's back.... Understanding the weird parts was my initiation into the world of JS 5 years back... it feels good to hear this voice once again :)

[@mrsnulch]

This is the best video on these concepts I’d seen, finally somebody explains it all and how it actually works under the hood. Kudos.

[@jacobbarr9217]

Tony, I used to learn from your Udemy courses about 5 years ago - as a junior developer... and I must say, I wouldn't be the programmer I am today without your courses. Thank you for being such an amazing instructor.

[@TonyAlicea]

Thanks Jacob, so glad to have been a part of your journey!

[@saienrique]

same here tony. thankyou

[@farazk9729]

Jacob, I am at the beginning of my journey. Could you do me a favor and tell me roughly how many hours it took you to land a job? I know it differs from person to person, but as I am doing self-study, I am a bit lost at times as to when I can see light (i.e. a job no matter how junior) at the end of this tunnel. I come from a strong background in human sciences but IT is a whole a new beast.. and at times I feel.. lost. I have no problem with hard work or studying deeply but I need to know how many hours it will take me to be able to financially rely on this new skill. Any help would be greatly appreciated.

[@saienrique]

@@farazk9729 Ideally it should not take more than 4 months to learn html css and javascript. if u do hardwork and with some hands on projects, u will easily get a entry level job.

[@farazk9729]

@@saienrique thanks Sai, but any idea abojt an hour-based time frame. I mean most people say 4 months, 6 months, 1 year, but how many hours does that mean? 4 hours a day? 2 hours a day? Thanks,

[@amerrashed6287]

after long time, so glad to hear the master who makes us loves and understands javascript, the weird parts!

[@puravidadino]

Tony, I am old school (top down) programmer.. I have reviewed countless docs, video, etc on how to handle async calls and all of them confused the bajeezus out of me. It is as if they all regurgitate the same pattern without a full understanding. Your "build your own promise from scratch" example really helps understand the incestuous nature of the the promise callbacks. I am slow, so I have had to watch it 10+ times at this point. (Luckily I can speed it up 1.75x) You are great orator and your examples are well thought. Up until your video I was your proverbial (imitate) guy. thank you

[@TonyAlicea]

Awesome Sean, so glad the video helped you gain understanding! That's the goal and I am always so happy to hear it.

[@ajkulin9]

Tony, i wouldn't be the dev I am today without you, 5 years ago I baught your course on Udemy and it was a life changer. I had some paradigm problems that you clear out and help me get the right method for future equivalents. Now I buy all your courses more for the interest and reassuring narration but also for the perfect content, and i'll enjoy your future react 18 course! Thanks for everything.

[@TonyAlicea]

Thanks so much. I'm so glad to have been part of your journey. Thanks for being a student!!

[@michaelguch3279]

Where is the "big word alert and breaking of glasses" hahahahahaha!!!

[@ashimov1970]

Having been eagerly searching for nearly a month for a clear, comprehensive and concise explanation of the Promise concept I finally arrived at this superb video. Thank you very much indeed, Tony, for the great job, and God bless

[@stormcoast910]

Thank you, thank you, thank you. All these mysteries under the hood. They don‘t let me sleep. Now you‘ve chased away the monsters.

[@scottpennell8900]

Excellent video. This took all of the mystery away for async/await/Promises and Thenable!

[@RajatKhare619]

This is the best explanation of promises I've seen so far. I really hope you start publishing full-length courses again!

[@ashimov1970]

Yep, it ABSOLUTELY is. I couldn't agree more

[@jacobcombe2012]

Thankyou so much! Your video made promises and async sound like something a normal person may have designed, rather than some over-complicated thing someone created to show off how smart they were.

[@TonyAlicea]

Thanks Jacob!

[@Alex-rt3ld]

Tony, you must keep on teaching people. You have good skills in it!

[@JamesJon1187]

This helped me get a much deeper understanding of how promises work. Thanks!!

[@msx47_]

Exactly what I was hoping you'd update in the udemy course but here you are with the free YT version. Amazing

[@jesusmendoza7774]

You are the best Tony. Big fan of your courses, they helped me a lot when I was starting programming and thanks to you I found my very first job 4 years ago, I still go back and watch some lectures to refresh some concepts. I hope you are doing well

[@michaelfishman3254]

Glad to see you are well Tony. Your Udemy JS courses were the first courses i picked up from their platform a few years back. I was confused and saddened when i reached a point in one of them where it seemed to abruptly end. I'm glad to see you are back and hopefully there was no serious problem in the past few years. Thankful for you continuing to share your knowledge with us.

[@ameensams]

Thorough, insightful, straight to the point and zero theatrics. Thanks!

[@nhanth]

Hey Tony, You are one of the most great instructors in the Internet. Thanks a lot for this sharing

[@sriramkrishnan9891]

Tony is back. One of the best teachers

[@TutorOfMath]

I'm sure Not everyone can handle your lectures in one sitting, but those that do, make a huge leap in little time. Your work ethic in explaining is beyond remarkable.

[@kshitijeminem]

Best explanation I have ever seen. Simply amazing!

[@OnsoDev]

Tony you back! Love the philosophy and methods of your teaching style!

[@drakegabrielvereto8423]

Whoa your explanation is SO MUCH BETTER than the usual ones. Thanks a lot, mate!

[@baware80]

Tony is a master and a GEM to JS, please do a full new updated course I will buy 10 copies just to support your amazing teaching style and in-depth knowledge.

[@ajitnain]

29:05 Very important and subtle thing, when we return a promise instead of a simple value from the function then this returned promise got synced with the promise returned by the next then function. Thanks Tony for crystal clear explanation.

[@hackingguy]

Can u explain how can I write that thing in CustomPromise Written By Tony! I was getting confused in this part a little bit!

[@hackingguy]

Is callback is being executed inside another promise?

[@eligoykhberg1807]

Yessssss!! Best instructor ever!!!! The nodejs Udemy course helped me big time, Thanks again!!

[@fonzanedelungini]

You are the teacher who had the biggest impact on me becoming a dev :)

[@relee24]

So glad to see you posting more vids Tony. I'm one of those people that can't just do, I have to know how and why things work. Your Udemy classes were the only ones that ever helped me make sense of programming even though I never pursued it as a career. Love ya man, keep being awesome.

[@topsecret9174]

That was the best Promise concept explanation what I'd ever herd before! That''s amazing, you really have talent to teach other people and much more, you have telant to explain comlex things at the simple way.

[@ManontheBroadcast]

By far the best explanation, as always after all ... so glad you are back !!! ...

[@TryX420]

I really have to say that this explanation is absolutely amazing, this was what I was looking for. It is absolutely well thought out and explained perfectly. Subbed to you and looking for new upcoming work! I am trying to become a Web Dev and hopefully you'll have more Web Dev related content! Thanks again.

[@TonyAlicea]

Thanks so much! More content to come!

[@eltonleao3979]

Simply fantastic! Thank you.

[@83bakr]

I'm a big fan of your courses since the js the weird part, without it I could not understand js, i have watched so many others courses non like yours, please continue your courses, the world of development needs you!

[@imtanuki4106]

Don't imitate, understand? What a novel idea...this is possibly the only vid on JS concepts that actually discusses...the concepts. There are very few instructional videos that fall into the "amazing" category - this is one of them.

[@semperfiArs]

Sir please continue this series. Thanks a lot for these concept videos

[@sagargopale5747]

Hi Tony, Welcome back, Even I liked the video before watching and this is because of the trust and your way of teaching.

[@flaviohenrique5294]

man, i see this video 6 times, the .then code wasn't make sense untill i understand that resolve is call after the function pass inside "than" it's alredy push to handler. your video is gold, tank you for sharing!

[@SeaRich]

Hope you keep updating, so helpful, thanks!

[@libraryuniverse]

hi tony your courses helped me a looooooot to understand javascript and nodejs. I was wondering what have you been up to since 2015 and worrying a bit if you are healthy and happy! it is so good to see that you are back! I can not wait for your CSS / HTML course. Please release it before Christmas, that would be the perfect gift for me!

[@user-mo3cw6go7c]

Wow you blew my mind Amazing! Amazing! Amazing!

[@TheDvayers]

In the world of web dev tutorials, there are many jokers and many pretenders. But there is only one jedi master , Tony Alicea.

[@manimohan8567]

One of best video I have ever seen. Please post more videos on JS 🙏

[@wilfredovillegas4231]

Awesome Tony, good to know you're back. 🙂

[@VinaySingh-cf6kd]

Tony...your videos make my day. Thanks

[@digitaldevboss324]

Dude I was like I wish this guy was around while I was learning earlier on....but I learn so much from you already. Glad you are back. This is something very lacking. I can code a lot of stuff now, but I can't say I understand why I'm doing some of it.

[@user-mo3cw6go7c]

You are the best 💖💖💖 by far!!!

[@levatruskavec2199]

спасибо тебе Тони !!!

[@atishraina6823]

Thanks Tony! This is wonderfully explained. I usually don't comment on youtube videos but I had to! You angular JS, Javascript and node courses on Udemy were life changers. It would be extremely useful for programmer community if you could have something similar on other JS framewroks (React, Vue etc)

[@urbanframesph258]

Thank you so much for this tutorial! Now I understand how Javascript Engine execute the Promises. I will surely buy your udemy course! I was stuck how the callback that is passed in the .then method as argument gets called/invoked, so happy I saw this video. Thank!

[@jijojoseph8721]

I don't have to imitate now , i understand better now. Thanks a lot and awaiting for further video's on the series.

[@pranavbhat92]

Amazing content! Thank you...

[@gianpierrefernandez7328]

Tony, Im looking forward for more of your courses... React, Typescript,.... 😀

[@andrewhull3590]

best video on youtube for asynch :)

[@TonyAlicea]

Thanks, Andrew!

[@inaminute00]

Been watching this multiple times, so that I don't imitate it, but understand

[@edgeeffect]

I've been searching for a straightforward into/tutorial for hours! This is excellent. Hand coding what the built in promise object does is superb.... although Douglas Crockford would frown on your usage of the `new` operator.

[@TonyAlicea]

Thanks so much!

[@slappy_chimp]

I was super happy with your JavaScript course.. learned a lot from it . And keeping it as a future reference in case i forget a concept. I just bought the node js course.. And I have high hopes for it :D I did nodejs from tutorials before stuff work but I never felt like I was learning.. Thank you for being an awesome teacher :D

[@TonyAlicea]

Thanks and thanks for being a student!

[@settahkader]

thank you so much , helpful video as always

[@frankie_goestohollywood]

Thank you, Tony. As usual...excellence 🤓🙏🏆⚜💯

[@TonyAlicea]

Thanks Francesca!

[@foobars3816]

Why did I not have the bell icon clicked!!! So glad I searched for your channel. One thing I would really love is a course by you about Typescript. Wrapping my head around it is driving me crazy.

[@captainanunnaki7646]

Man, I don't know why I am not trying to insult you in fact your videos are actually the videos that unstuck me when learning to code and I think you have the gift of teaching that not many people have but every time I watch you I fall asleep xdddd but not because it's boring, actually I am really interested in your videos because you explain things the way that it should be taught especially for beginners but I just fall asleep, I don't know why I have no idea, I am really interested in what you teach and in the way you teach it but I fall asleep. I absolutely love your course and your videos they are unique and you teach things that other people should but don't. Thats one of the strangest things that ever happened to me, every time I watch your videos I fall asleep I am really not trying to offend you, just thought I should share this cuz it's really strange, it's not meant to be a roast it's just a strange thing that happens. I feel like if you sing me a lullaby you gonna knock me out cold in minutes:DDDD Every time I see you uploaded a video I get hyped but I just know I have to make myself a huge cup of coffee before watching, it's like a strange ritual I have :DDD Believe me you have a gift, it takes me hours some times to put my kids to sleep I wish I had your skill :DDD Hope that doesn't discourage or offend you I think it has some psychological thing about it based on the tonality of your voice or something I don't know but keep up the good work your videos are more than amazing you are part of the 1% of teachers that teach for real so that everyone can understand. A lot of KZbinrs do the opposite, they explain in a way suitable for them and assume you watch their videos with a programming dictionary in hand.

[@vitez-koja]

Welcome back Tony!

[@Frankslaboratory]

This is such a GOOD explanation!!!!!!!!!!!!!!!!!!!!!!!!!

[@evenaicantfigurethisout]

tony, i was just going through your weird parts again recently. never gets old. i just wish you did a whole weird parts part 2 to get up to speed with all that's changed since then. do you think you can make video here on youtube about all the queues? tasks, microtasks, queues, schedules. jake archibald's talk was only very slightly enlightening for me. it had nice animation but i got very little out of it in the end. plus it didn't touch on microtasks.

[@monstardev7189]

Hello, i've struggled for years to find a good place/person to teach me javascript with little to no success. This led me to deeply believe programming wasn't for me and that maybe I wasn't smart enough. Yet I came accross your js tutorial on Udemy and even though english is not even my native language I absolutly loved it, the way you explained how things work in details was all I ever needed. I finaly have the tools and can code comfortably. It feels amazing. I look forward to see more content from you, maybe some Reactjs tutorials would be great as coding on such framework makes me wonder how things work under the hood so I could reach its full potential. Thank you and Merry Christmass :)

[@sathyaneshkrishnan4657]

Nice, Welcome Back !!!

[@jenso413]

woah, what an informative, well-thought out video. really helped me to understand promises better. thank you!

[@TonyAlicea]

You’re welcome, thanks Michael!

[@alexanderlindgren3504]

Any chance you can make a tutorial on react Tony? Love your courses on node and Javascript.

[@mindas22]

I don't watch netflix and hangout, I watch Your videos and hangout :D

[@candi2Love]

Thank you.

[@oene2830]

This is definitely the best video on promises. Very helpfull 🙌

[@TonyAlicea]

Thanks so much, glad it was helpful!

[@radu9150]

Amazing content

[@saurabhchauhan232]

If someone is c# developer, I recommend Shivkumar channel. He's as excellent as Tony. I hope Tony and Shiv both get much attention and their talent reach to most of the people to help them better.

[@frankie_goestohollywood]

I am very much looking forward to your upcoming React course! 🤓😁👍🏆💯

[@ranjaninatarajasharma5917]

Music to my ears . Big fan Sir

[@abderahmaneaoufi]

Thank u so much this helped me a lot!

[@teerapatprommarak2070]

Wowwww You're back!

[@bz101]

Wow! Really demonstrates how promises work! I was just lost with promise, and it seemed to me like nobody really explained the inner logic with how promises. I was always wondering what the “resolve”parameter was handled by the promise object. I wouldn’t say I am 100 percent confident with it, but still helped tremendously.

[@TonyAlicea]

Thanks!

[@farhan_aftab]

Welcome Back Sir

[@tictac1020]

Ahaha after watching The Weird Parts years ago, it was super funny to see the Big Word Alert towards the end of this vid. I haven't watched any other vids of yours in a while so it caught me off guard.

[@andrewwebb2866]

Ah, you're back! Good man. Have we got an ES6 Udemy course coming?? ;)

[@TonyAlicea]

More ES6 content will be added to my existing JavaScript course next year.

[@tamilkum]

Hi Tony, I love JavaScript only after knowing its internals. Your Udemy course only gave me the clear understanding of its internal. This tutorial gave me a clear picture of Async, Await and Promise. Thank you very much.

[@TonyAlicea]

Great, thanks Karpak!

[@hericklenin]

Esto es filigrana. Gracias.

[@bowser_inthe_darkworld2]

just amazing

[@TonyAlicea]

Thanks!

[@harshbiyani3048]

Awesome explanation 👍

[@MuhammadAli-sx1qv]

God bless you, Tony, You are the Best, Big Thanks to you, how could I get to the level at which I could think logically and implement any feature in general like that how could I get that skill?

[@bernarddt]

Kudos on an amazing video. starting at the beginning and explaining your thought process is extremely well received. Anticipating what could be asked by a beginner at the start and later by more advanced programmers is very well done. Even how you animate the text slides helps follow your or basically our thought pattern. I'm considering looking up your Udemy courses to fast-track my JavaScript knowledge if this is the standard you work by. Edit: Ok correction I just signed up for the Udemy course... There is no way this could be a bad investment :)

[@Buanaoda10]

Hello Tony! when does your Relational Database Design and SQL course gets launched? Need to learn this ASAP. Thank you very much for your courses, they are great, and really inspired me!

[@Flexo1986]

JS Understanding The Weird Parts was instrumental for improving my understanding of JS. And this is just the video I need :)

[@TonyAlicea]

Great! Happy to have been part of your journey.

[@Flexo1986]

@@TonyAlicea question regarding the Node.js course ... is it "evergreen" like JS: The Weird Parts or do you think you have to update it a bit? Thinking about learning Node.js and your course seems like the way to go :) Thank you!

[@TonyAlicea]

@Flexo1986 There are a few things in the course that need updating, but the vast majority is still fine because its about what Node really is and how it works under the hood. I am pleased that many people still recommend it as the best course to start with.

[@Flexo1986]

@@TonyAlicea thank you for the reply! I'll get the Node course too! And let me tell you that if/when you decide to "revamp" the course, I'd be glad to pre-order it ... and I'm sure a lot of other people would do the same :) And you might as well make your own educational platform!

[@soufianesammah5936]

Can you do PART 2 of this video, please!

[@salilbajaj4296]

Satisfaction @34:35.. Nostalgia :')

[@AB-cn6iu]

I know most of this already. I just clicked on this video to hear your voice again.

[@TonyAlicea]

Aw thanks!

[@Frank-vm7vm]

Tony plz create a course on es6 you are the best JavaScript instructor ever, loved your understanding the wierd parts course. Plz come back soon we need you

[@TonyAlicea]

First quarter of next year, I will be adding ES6 content to my existing JavaScript course.

[@revisionnaire]

lol is it just me who watched this video 'several' times before it fully sank in? Regardless, Thanks super much Tony, i have done the AngularJS course and just about to finish the NodeJS. They are really super-helpful and super insightful as an upcoming dev. Plus your philosophy, 'Don't imitate, understand' i think i always felt that way ever since i became a teenager. I have seen your HTML and CSS and i will ofcourse go on that as well in the near future.

[@sanjibmondal9107]

Thanks sir after long time 🙏🙏🙏

[@Cutrexxx]

I finally got it. Thank you verry much!!!

[@TonyAlicea]

You’re welcome!