JavaScript Promises -- Tutorial for Beginners

JavaScript Promises and all their glory! This is episode 12 in a 10 part series I’m calling 10 things Javascript Developers Should Know But Probably Don't.
JavaScript Promises
Different phases of a Promise
Chaining Promises
Handling errors using Promises
Benefits over callbacks and callback hell
What do they all mean and why do you need them?
Full playlist here: • 20 Things JavaScript D...
JavaScript Promises from the series "10 Things JS Developers Should Know"
by ColorCode.io, Sina Jazayeri
** Announcement **
Full JavaScript Mastery course is coming! Details at the end of the video. Sign up for Early Access here:
www.colorcode.io/js-mastery
0:00:00 Intro
0:01:48 Async vs. Sync
0:03:29 The problem with Async
0:07:00 Convert to Callback
0:08:00 Convert to Promises
0:10:32 Different phases of a Promise
0:11:47 How to use a Promise
0:14:47 Why do we like Promises?
0:16:30 Chaining
0:20:59 Benefits of Promises over Callbacks
0:22:50 Error handling, REJECT and .catch()
0:30:23 .finally()
0:31:50 Real world example with fetch()
0:34:30 Summary
0:35:13 Next...

[@ColorCodeio]

🎉👨🏻‍💻 JavaScript Promises and all their glory! This is episode 12 of a 10 part series I’m calling 10 things Javascript Developers Should Know But Probably Don't. Enjoy!

[@onlineaid]

Amazing series :)

[@DanielNetSet]

12 out of 10? thats a out of bounds/stack overflow

[@davidhusted817]

You promise 10 episodes but now in 12 😂😂

[@extreme8879]

Promises

[@kiranrega10]

Which js compiler are you using?

[@user-gi3oc1kv5m]

I’ve been watching videos for years trying to make sense of Promises, and while I got through it, I’ve always wanted to come back and really understand them. Your video turned the light bulb on for me. Wow! I had to tip you for the help! I appreciate it so much! Definitely subscribing!

[@ColorCodeio]

That’s so great to hear. Thanks for sharing.

[@deveren]

@@doublewhopper67 ure da g

[@Saliha_Abid]

I am a 15 year old learning front-end development and struggling with promises. After 3 days of exhaustion I found ur video and finally got the whole concept. Thank you for this masterpiece 😍😍

[@amanueletana]

This is not only coding tutorial rather its an ART!

[@ColorCodeio]

♥️🙏

[@carsten1223]

I just came across your channel. You have a really great way of explaining things and giving them some context. Thumbs up 👍and I'm looking forward to hopefully many more videos like this!

[@stephenkettley]

Man your content is so insightful and relaxed at the same time! Loving it.

[@user-eq9gs7bl2e]

i can tell you put a lot of passion and effort into your work bro its inspiring

[@AJD...]

Been watching your shorts for a while, decided to hop into your channel and this is the first video I watched. Holy hell the quality of your videos is mind blowing. You put so much effort into edits and your explanation is very planned, with a set preordained path which makes the most sense. You've got a new sub.

[@ColorCodeio]

Thanks AJD. Very nice of you.

[@lemonbubble1243]

3 days ago I wanted to watch just this video but the title made me look for the whole series, and I knew that to understand better I needed to watch the previous episodes, and OMG I'M GLAD I DID. I feel I have like a super knowledge now, EVERYTHING MAKES SENSE NOW!! I don't know how to express how grateful I am!! I'm so excited because you cleared all my doubts about promises and not just promises, now I understand Objects() way better! THANKS!! Waiting for your master class!!

[@ColorCodeio]

Glad to hear it! Full course coming soon.

[@RaviCreative3-ge4ne]

eagerly waiting man @@ColorCodeio

[@xClown55]

There aren't many video's that are 30+ minutes worth rewatching, but this one certainly is. Nice video

[@toohee8561]

This will be the one video that gets me understand the basics concepts of promises. very good video outline and content.

[@bakenbard]

That was really helpful, I'm finally got the basics of it. THANK YOU!

[@BitWizCoder]

This is the first time I'm seeing this guy, 30 seconds into the video, and I had to subscribe. Thanks for the video and the fun!

[@AriKhuu]

I'm so happy to be finding your channel I want to cry. Impeccable production. Clear examples. Perfect pacing - not too fast, not too sluggish. Detailed yet very follow-able explanation. Funny host. thank you thank you thank you.

[@ColorCodeio]

Let’s cry together

[@bendustin7609]

Thank you for putting out such high quality videos!

[@Walid-Sahab]

جانی بہترین ہوگیا 🔥 🤍

[@ahmedAltariqi]

That was pretty well explained, and FUN to watch ! Thank you, Weather Man!

[@ColorCodeio]

Very welcome

[@mohamedabdulmueen2115]

I loved everything in this video man, keep it up !

[@guy_roh]

Thank you so much for making an actually apprehensive video that normal people can understand, explaining the why's and how's in a much better detail than a lot of other videos I've watched! Subscribed and added this to my favorites in case I should I need it in the future! 👍

[@ColorCodeio]

Thanks Guy!

[@user-kn4oi9oh4i]

Thank you so much for this!! ❤❤❤❤

[@ferreven2558]

Thank you so much for this video! Finally someone who can explain promises well.

[@ColorCodeio]

Glad it was helpful!

[@erickchavez4551]

I really like how your examples lead to real life situations and at the end it doesn't seem that complicated. Thanks!

[@ColorCodeio]

Thanks!

[@akasharthanur3057]

You are just awesome, keep up your work... Learnt a lot!! Thanks for this... I love JavaScript!!

[@chaoticthundergod3368]

Thank you for this video. Leaned a lot. I was learning about promises a year ago, didn't understand much so skimmed through it. But now i can explain to others what a promise is.

[@ColorCodeio]

Wonderful!

[@sars8374]

Amazing explanation! I have been enjoying your series quite a lot. Looking forward to other videos. Btw, there is a small error in the video, fetch by default returns a Promise, we don't need to create it ourselves :) Have a nice day/night!

[@raheem81kg]

Top quality as always

[@Gwgitu77]

Thanks for the clear explanation sir

[@nethunter1018]

Love the way you explain everything.❤❤ Can you make a video on hoisting in javascript and stuff like javascript execution context.

[@nitishgupta9585]

Bro your explanation of concepts is top notch. Keep the good work up!!

[@ColorCodeio]

Thanks Nitish

[@krypton_dev]

another GREAT video. Thanks a lot SINA

[@sh9vch9nk0]

Great video, clear and detailed!) Thank you a lot 😊🙏

[@proudmoroccan8164]

Thank you for sharing. Immensely appreciated. The best JavaScript promise tutorial as far as I am concerned. Best wishes for the new year.

[@ColorCodeio]

You are welcome!

[@jeffersonr.l2864]

This content is simply amazing! Thanks for your effort in creating quality content, I learn a lot thanks to it.

[@ColorCodeio]

Awesome!

[@onais__]

UUFFFFF The Chaining explanation was 🔥🔥🔥

[@rishayshandilya1817]

the best explanation of promises I promise :)

[@2difficult2do]

Thus is the best explanation of Promise! Thank you so much!

[@ColorCodeio]

You're very welcome!

[@web3withbeny]

Like the way that you teach, wonderful!

[@richardradcliffe6178]

Thank you. Looking forward to your video on async awaits!

[@ColorCodeio]

Thanks Richard. Coming soon.

[@codywatt7775]

I really enjoy your videos thank you for making them! What is this website you are using to see the results of your code as you type it?? so cool.

[@breemudi]

My first time ever watching you, and I'm intrigued by your tutoring style. Instant subscriber... Thank you

[@ColorCodeio]

Awesome, thank you!

[@Mashael_96]

Great explanation.. thank you 👏

[@johnnya246]

A very underrated channel. I like your style of teaching! Thank you for the content! Keep up the good work!

[@ColorCodeio]

Thank you

[@vighneshs416]

I stumbled upon your channel from a random KZbin shorts. I am very certain that soon you are going to be a lot of people's go-to channel for Javascript (Or anything that you make content on). The effort you put in to make the concepts intuitive is just top-notch. And I guess it is very evident from the other comments as well. Thanks for the effort you are putting in man

[@blaqhakym]

Exactly the same for me. Looks like I will be here for a while. I'm hitting sub right away

[@ColorCodeio]

Thank you both! Welcome aboard.

[@imtanuki4106]

Not sure if this is covered in another video, but a discussion of the event loop and micro/macro tasks might help put promises in context. Otherwise, great video!

[@sourikray2291]

You are a wonderful teacher. Thank you for creating these videos🙏

[@ColorCodeio]

Thank you!

[@jw200]

No Promises that I learned to Promise. Excellent tuts and explanations. Liked and subbed! Love your energy🙂

[@ColorCodeio]

Awesome! Thank you!

[@gaganbaghel1377]

THE BEST JS CHANNEL

[@Epikht]

Bro thank you for this amazing video

[@user-mw5bm2xh9x]

thanks for the lesson

[@godnonamesleft]

This is so well made. Thank you.

[@ColorCodeio]

🙏

[@sergeysviridenko9603]

you're the best of 7 videos about promises I've seen

[@ColorCodeio]

✋✌️

[@strangelight159]

5 minutes into the video and I can already tell that you are criminally underrated. Subbed

[@ColorCodeio]

Hah thank you

[@rjerez]

Great work Sina, this is a subject that a lot of people seem to get wrong on interviews. Now I can refer them to this video. 👍🏽

[@ColorCodeio]

Thank you Ronald for your support, always!

[@eumm11]

always great, you never disappoint!

[@ColorCodeio]

🙏

[@user-hs6jw1wm7i]

Lot's of gratitude from me here Js Master, this series is really impacting me...

[@ColorCodeio]

Glad to hear that ♥️

[@mikeyim9597]

Glad I found your channel. It's the best explanation of the Promise and Async Await. Can you please do a series on the same topic for database CRUD? Thank you.

[@ColorCodeio]

I'm considering doing one on CRUD operations with Firebase.

[@sarkorbekabdullaev9581]

Thank you bro, can't wait for Episode 13 Async/Await

[@ColorCodeio]

Coming soon

[@kayodekehinde3756]

Cheers what a beautiful Teaching thank you so much for this Video!!!

[@ColorCodeio]

Thanks for the comment Kayode

[@cjplabs]

I know this video is old, but i’ve been coming back to this “10 things you should know…” series every time one of these topics comes up in the Odin Project and they always just make everything click

[@nikolanovakovic4150]

Brooooooooooooo 🎆🎇❤🧡💛💚💙💜 first of alll, love your humor, second of all amazing content struturing it is so well organized an succinct and i will do what all the other people in the comment section did compliment how good your videos are. much love !

[@ColorCodeio]

Thank you so much

[@mansoormohmand5852]

I have seen lots of videos and tutorials but never use this topic of promises in my coding because of the bad and hard explanation, but now I am pretty sure I can use and refer to this great explanation ever, thanks a lot

[@ColorCodeio]

👍

[@alanouri9965]

Very smooth,keep up the good work bro

[@ColorCodeio]

Always

[@johnforeverrules]

thank you so much Mr Sina. Promises confused me a lot. God bless

[@ColorCodeio]

Glad to hear that

[@m47h4r]

29:10 A usecase for passing in onError in the .then() is to provide fallback data. For example, if fun1 rejects and then if the onError returns some data, then having fun1().then(fun2, onError).then(onSuccess) means that the onSuccess function will always receive some data, either fun1 resolves successfully and it's all good and well, or onError happens and that provides a fallback value so that onSuccess can always assume it has some data.

[@abahiduh3246]

I have watched the best vidoes of Kyle Simpson, Tyler McGinnis, Tony Alicea, colt Steele, Jim cooper, Aksay, Ania, Maximilian, Sasha, I can go on and on.... I spent A LOT of Money just to understand. I have watched ALL YOUR VIDEOS. I can assure you that this explanation got.YOUR EXPLANATION of SIMPLIFYING THE CODE before refactoring in simply the Best. Your tutorial is AMONGST THE BEST THREE for me. THANK YOU, THANK YOU, THANK YOU.

[@ColorCodeio]

Thank you so much. This is very encouraging to hear.

[@mashmixture5662]

Learn alot from ColorCode in just one month. Such an amazing content. The way you explain things is very very very interesting and funny. *Best JS channel* on KZbin. Thanks for such a premium content. Please deliver more.

[@ColorCodeio]

Thanks a lot

[@16NaruSasuke]

Thank you very much. Your videos are awesome, it is very clear what you are saying.

[@ColorCodeio]

Awesome! 🤘🏼

[@StPQW]

You rock!! 👑Thanks so much for your work!

[@ColorCodeio]

Thank ya! 🙏🏼

[@theshtig4218]

GOATED video. This will be the last promise video I ever watch. Thank you!

[@ColorCodeio]

Appreciate it

[@msunrl8577]

24:28 u so right about repeating and coding from scratch again and again, this so important to memorize and practice some hands on great tutorial, thanks

[@ColorCodeio]

🙏

[@RoockYou]

Your explanation is so funny and so helpful at the same time, Hope you keep doing videos this way

[@ColorCodeio]

Ty!

[@Epikht]

i'm gonna comment fort the third time, that is the best video about Promise all over this app I spend 2 days on it, messing around with my own things Thanks a lot Color Code

[@ColorCodeio]

That’s awesome. Glad to hear it.

[@khalidsaifullahfuad]

Loved the intro 🔥.

[@ColorCodeio]

Thanks 🔥

[@nucleareggdevar]

Phenomenal. Beyond phenomenal.

[@ColorCodeio]

:)

[@matickovac]

This is by far the best explanation on the topic I have been able to find, and I must say I love your other videos as well. Love the production quality too, what is the recording software you're using, looks really slick?

[@ColorCodeio]

The animations are all done by hand. The screen recording is just basic QuickTime.

[@theultimategamer7202]

Great content as usual. Please upload video consistently

[@ColorCodeio]

👍

[@blu3tan]

nice setup, nice host, nice code, nice music, nice edit, nice english

[@avigarg7859]

You teach so creatively

[@ColorCodeio]

Thanks

[@tanjimulislamsabbir2264]

Wow. That's a great one about promises. 💚

[@ColorCodeio]

🙏

[@pandorofortes9309]

Thank you for the knowledge😁😁😁 Your channel is🔥🔥🔥🔥🔥

[@ColorCodeio]

I appreciate that!

[@GusGabriel]

Thank you so much for your lessons, and have some fun coding also 😊😊

[@ColorCodeio]

That's the goal!

[@ajayrathod7438]

I loved your video like every other specially your sence of humor. Can you make one video on Promise.All if possible.

[@ColorCodeio]

👍

[@bluelion978]

Fantastic!!

[@hamraj1983]

Thanks for making it so easy to understand..🎉

[@ColorCodeio]

👍👍

[@mira10045]

Please keep this JS series. I like your explanation!

[@ColorCodeio]

It's going to continue :)

[@hao12654]

@@ColorCodeio really nice video, please do continue!

[@CondeAlberto]

Waiting for episode 13... Qoly! Thank you for the video.

[@ColorCodeio]

I just spoke to Qoli. He says hi Alberto 👋

[@CondeAlberto]

@@ColorCodeio 😄

[@ashaymotiwala96]

Best Javascript tutorials on YT!

[@ColorCodeio]

Ty!

[@samirneupane7563]

Great .Thank you so much.

[@xenocampanoli815]

BTW your "do it yourself" admonition reminds me of the advice at the beginning of all the old Charles Berlitz language tapes where he said: Read it, Hear it, Speak it. He may have also said "Write it" sometimes, but his point was memory reinforcement that is as functional as possible.

[@ColorCodeio]

🙏♥️

[@yiroyi2894]

Your videos are amazing, very clear, it helped me a lot to finally understand the Promise concept

[@ColorCodeio]

Amazing

[@proghead00]

Have been watching your videos for a while. The production value is so good. Just wondering, what's this code editor that you're using here?

[@ColorCodeio]

RunJS

[@philliam111]

very underrated channel! glad i found you

[@ColorCodeio]

Welcome aboard!

[@aleksazlatkovic4663]

What a charismatic person you are. Good Lord. I started the video knowing nothing about Promises and I am finishing it as an absolute pro. Thank you for going into detail.

[@ColorCodeio]

Thank you. Made my day.

[@TsipporahtheExplorer]

"im sick and tired of your broken promises, promises" -3LW Thanks for always upholding your end of the promise Sina!

[@hiranga]

Great tutorial! 💪🏾💪🏾Was wondering if your code editor setup is possible to achieve in Vscode?

[@ColorCodeio]

RunJS.app/ColorCode

[@EducationSimplified]

Awesome explanation, I thought it was a difficult thing but you made it way tooo simple. Thank you for your time and efforts. God may bless you a lot.❤❤

[@ColorCodeio]

Thank you!

[@ciprianparaschiv7591]

Thanks for being so important in my JS journey. :) Btw, is that Quokka for JS that is displaying your code 'preview'?

[@ColorCodeio]

RunJS.app/ColorCode

[@th3ja]

Top notch content!

[@ColorCodeio]

🙏

[@saeed.da1994]

you are amazing! Your act is awesome! I see you as Iron Man in Marvel (Robert Downey Jr.) :))) In my opinion, your videos in Promise and Fetch API are the best video that I've ever seen in the internet! It's funny how you suddenly mention Gholi in your video :))) who is hi? :) are you from Iran? :))

[@rohanagrawal5747]

yeeeee i was waiting for this video