JavaScript Visualized - Event Loop, Web APIs, (Micro)task Queue
HTML-код
- Опубликовано: 14 июн 2024
- Learn how the browser event loop, task queue, microtask queue, and Web APIs work together to enable non-blocking, asynchronous JavaScript.
- / lydiahallie
- buymeacoffee.com/lydiahallie
- / lydiahallie
- / lydia-hallie
- / theavocoder
Timestamps:
0:00 Intro
0:32 Call Stack
1:18 Single-threaded Problem
2:01 Web APIs
2:47 Callback-based APIs
4:04 Task Queue
4:39 setTimeout
6:22 Microtask Queue
8:40 Promisifying Callbacks
8:57 Challenge
10:52 Recap
11:58 Outro
Btw if you're in a hurry you can just fast-forward to 10:52 haha! I use Apple Keynote for everything.
💡Just a heads up: I explain these concepts in a way that personally helped me conceptualize the processing order.
E.g. the event loop doesn't directly "prioritize" the microtask queue, rather they're just processed and completed before the event loop continues to the next task. One iteration of the event loop is executing a single task, processing all available microtasks, and then updating the rendering of the page if needed (that's not covered in this video, might be another video, things like requestAnimationFrame). However, within your code, you'll get the sense that the microtasks are "prioritized" over the task queue-based parts.
Gotta love you for respecting our time.
From where did you learn?
Can you please extend this more to explain NodeJS runtime 🙏
Those slides are wonderful, it’s still a mystery to me how they are so good. Skills.
Thank you for doing this. I love the visuals you made here!
i think thousands of senior developers finally understood it today.
🤯
fake senior developers. No theory , not a real dev!
Knowing the todays reality, you wanted to say "junior" developers ? : )
@@KAIDO-mi1tr haha
now adays, senior and junior have similar salary, so whats the difference
Where has this channel been all my life?
Exactly I was thinking the same 😂
In the future obviously. 😂
She already done a longer vid for freeCodeCamp 2 years ago and she's on FrontedMasters as Teacher
ruclips.net/video/xckH5s3UuX4/видео.html
Same here❤❤❤❤❤
Exactly!!
I have been programming for 15 years and I don't think I have seen information presented so succinctly in that span. Thank you so much for this.
100%
Absolutely 🤟
This video should receive the Oscar for best animation
I've been in software development for 16 years. This video is outstanding. Probably one of the best I've ever seen for JavaScript.
Lydia, I want to encourage you to keep doing these if you desire. This visual, animated approach combined with your ability to teach is a home run.
Thank you so much for doing this. I am now subscribed.
9 years ago was this video... her video seems a rip-off
ruclips.net/video/8aGhZQkoFbQ/видео.html&ab_channel=JSConf
I can only agree. Especially for this topic, it was hard to find such an amazing explanation. You really helped me out. Thank you,
ditto
@Lydia Hallie Are you kidding? This level of detail, every animation, every transition, the highlighting (and temporarily hiding unimportant components) is just so good.
Very well done, love it.
it is very very rare to have material like this presented in such a visual and engaging way .. animation is hardly ever used in js tutorials. Visualization of these concepts is so important for the visual learners out there. THANK YOU.
instantly subscribed.
wow the visualization is awesome. The colours, gradients, design and animation. Its perfect down to the tiny details.
If anyone had a question in the Challenge section as to why console.log(1) didn't execute immediately, even though it was in the Microtask Queue and the Call Stack was empty, read on.
All the code on the left is a script and can be represented as an anonymous function. At the very beginning of the "Challenge" section in the Call Stack, there should have been an "anonymous" block. This block starts executing (the script is being executed), and then everything is the same as in the video, except that the "anonymous" block is always at the bottom of the Call Stack. The "anonymous" block disappears from the Call Stack after console.log(5) is executed, because it is the last operation in the script.
And so when the "anonymous" block disappears from the Call Stack, Microtask Queue and Task Queue processing starts (10:04).
Great video!
Thank you. Absolutely wondered this.
Yep, the anonymous block is referred to as Global Execution Context
The sign of mastery is being able to simply explain a complicated concept. This preso is a thing of beauty... and mastery!
This presentation is a pinnacle of visual communication. We are dealing here with a highly organized mind.
Okay ma'am, I noticed you only have 3 videos on your channel. Don't stop until you have at least a 20 video playlist on your channel. This is gold.
This is the type of visualization that coding vids need
it reminds me of debuggers we used to have in the late 80ies
I'm a web programmer for 15+ years now and I'm stunned how well made this explanation is. really Amazing! Subscribed right away!
Top tier presentation, this is easily one of the best visualizations I've seen on RUclips. You clearly have excellent teaching and communication skills. I know you are focusing your content on JavaScript but if you were ever interested in giving us an overview of some of your presentation techniques in Apple Keynote, I think many viewers could greatly benefit from it.
Keep up the awesome content! I can't wait to see what videos you have in store for this channel.
Hands down, the best event loop explanation ever!
I finally understand Event Loop after 1 year writing JS.
Don't worry, many devs still don't understand it after 10 years of writing JS.
I thought I did… until today😅
No you do not 😂
huh do you need to understand it? coding js/ts for 3 years now
Then you're a shit developer tbh
Thank you.
This is the best explanation I've seen.
10 / 10 quality. The explanation of the different queues helped clear up confusion I had in the background of how asynchronous tasks work underneath the hood in the context of Javascript. Even with a bachelor's degree in computer science it was still a pretty head scratching concept thinking "how does the engine know what is I/O blocking and what is not? How does it handle that?". I would always hear "oh its just on the event loop! Its just on the event loop!" but I'd be like "all these diagrams suggest the blocking and non-blocking are on the same queue". I had no idea about the microtask queue and that is where fetch's then calls are appended to.
Also I can't help but look at the word "event loop" and just think of Froot Loops.
The visualization is outstanding, providing one of the clearest and most informative explanations I've come across.
Lydia, your teaching style is the best I've seen. Please continue to educate us.
This video brilliantly illustrates the intricate workings of JavaScript's Event Loop, Web APIs, and (Micro)task Queue. The visuals make complex concepts crystal clear, making it easier to grasp how JavaScript manages asynchronous tasks behind the scenes. Kudos to the creators.
one of the best video on javascript visulization.
thank you lydia Hallie.
Make more videos like this.
Whoa, I'm so happy that this channel exists. The visuals help SO MUCH with understanding all the JS flow!
Whoaaaa... Ive been writing js for years and this is hands down the BEST event loop video resource ive ever seen. My god its presented so simply! 💯
can not be simpler and more elegant way of showing the concepts, thanks for the lessons.
By far the most simple yet effective way to show event loop . Really enjoyed it
Fucking hell Lydia, this is incredible
Ah thank you Matt! 🙏
Mam can you make a video on how exactly the react works under the hood ?
This is the best topic
12 min just recalled my last 2 years ❤🎉
this single video has taught me more about js under the hood then months of watching other videos
Are you Ai? This seems too perfect
*too (This has been your ai powered nostalgia post troll, have a nice day.)
I think this is the best event loop explanation in the internet. You have described each and every point in such detailed way, making this topic feel so simple to understand. The animation is also made with such detail, making life easier.
This presentation is crazy good. I can only imagine the amount of work put into it. Congratulations.
I have been programming for some years now, as a visual learner this video was awesome. Perfectly visualized and straight to the point! Keep up the great work
Never thought I grab some popcorn🍿 to learn about the inner workings of JavaScript, yet here I am. Awesome work!
This channel is a gold mine, thanks for sharing it, this is amazing
One of the best explainer videos I've ever seen, thank you! Subbed
This was absolutely amazing!! The way you broke down callbacks from methods, visuals to see what’s happening. Best of all a challenge to really help drive the subject home, best way to improve learning. I can’t wait for more to come from you and THANK YOU!
Been doing javascript for over a decade, and this was the coolest explanation I've ever seen!
Pls, don't stop making videos like this, it's really enlightening!❤
You just got yourself a new subscriber! I actually watched a video about all these a few days ago and I kinda understood how it all works but this video is the icing on the cake, I now perfectly understand how it all works and it's all thanks to the beautiful visualizations you used and your straightforward explanation. This video is a goldmine ✅
Amazingly simple explaniation and satisfying graphics! Really thankful for this video. Keep it up!
You are an amazing tutor. The visualization is incredible.
Lydia, your explanation is by far the clearest i've seen out there. I'd love to watch something similar for async-await!
The best visualisation of the JS runtime I've ever seen! Respect Lydia!
Best possible explanation out there for understanding event loop concept in JS. Thanks for the video.
These videos are extremely well presented!
This is excellent work, Lydia! Your visualization of the event loop definitely can help millions of JS engineers understand it better. Huge impact, congratulations!
4 months ago, I learned event loop from your dev.to post titled JavaScript Visualized: Event Loop - which is the best visualised minimalistic explanation I have come across, and then to refresh it, I watched this video you recently posted.
Thank you Lydia Hallie.
I'm preparing for an interview and this helps a lot. The promises video and this one are simply incredible. Love the series.
I've already learned all this, but this is the probably the clearest, best, and most beautiful explanation I've seen. I need to share this...
I already knew all these but still watched it because of the quality of your presentation.
Great work.
Keep doing what you're doing.
One of the best video ever that explains concepts this clear. 🙌
This is phenomenal. I just started learning javascript coming from an Embedded systems background and never understood how the execution of commands happened. This cleared a year of misconceptions for me and unprecedented years of troubles. Wow! Some people are just goated!
Ridiculously simple when you explain it. You just got new subscriber !
So great! I love this kind of explanation with animations! It makes complicated concepts so much easier to understand! Thank you very much for the video!
It's so well explained that after 1minutes 27 seconds of watching I had to subscribe. This is pure quality content
God bless you Lydia. Hands down the most important and enlightening JavaScript tutorial on the RUclips that every serious JavaScript developer needs. God
Best video ive seen on this subject. The visuals help a lot!
Thank you, Lydia. You explain very well. After 3 years writing JS, I'm finally taking the time to go back to the basics and learn the fundamentals and I'm learning a lot
I've never seen this information provided with such uncompromising clarity. Subbed. This is the first video I've seen of yours, but if the rest are anything like this one, you're worth it. Amazing.
So far the best explanation of how Java script works. Thanks
I am in awe of the explanation and the masterful use of Keynote. Great stuff. Congrats!
Your explanations are crystal clear and your slides are absolutely stunning! You have a real talent for breaking down complex topics in such an engaging way. Keep up the fantastic work, you're making learning an absolute pleasure!
I've been dreaming of one day creating such video for years. I'm happy seeing someone did it beautifully, especially when it is a soft spoken girl.
Thank you! This is absolutely the best explanation I have ever seen. 12 mins of video cleared out all the my confusions I had in event loop from day 1!!
Best event look explanation video I’ve seen
Awesome work! ❤
This is absolute gold! So glad RUclips recommended this video. Lydia, it is amazing to see the effort you've put into creating these slides.
I subscribed in the first 60 seconds. This is how the universities should have taught us! Kudos! Looking forward to your next one!
Hope you keep doing this great job. This is one of the best explanations I've seen in the last few months.
Your presentation is absolute the best event loop explanation I ever saw. Thank you and congratulations in doing such amazing work to help other people.
Thank you so much for presenting this topic, Lydia.
this is the best ever explanation i've ever seen... Thank you for this amazing video
The best explanation and visualisation! Kudos!
Instant subscription!
I can't imagine the amount of work you put in to explain something so complex put so simply
Congrats on this video. I've read a lot about this topic... articles, tweets, book passages. I've seen videos and talks about this. None of them were so thorough, clear and enlightening as this one. Keep up with the outstanding work!
That's a really good way to explain something which can be complex trying to understand it without the visualization! Thanks alot for sharing this gold content!
What you've done is mind-blowing, ma'am.
This is brilliant! Such clarity💎😄Thank You!
This has saved my sanity on something I thought I could never understand.
This channel is a gold mine... literally.. please post more.
Este video es INCREIBLE. Completamente deberia ser un MUST en cualquier capacitación/universidad. Millones de gracias!
The presentation and clarity of this information is excellent! Thank you for making this video. It made understanding the Event Loop so much easier!
This is the best video that I have watched about how works the event loop
It is one of the best explanation that i ever had
I've just came across your channel.
Very concise, informative and pleasantly visualised.
Also interesting topic!
This is the best video on this topic I’ve ever seen. And I’ve seen many
You made it easy for me to understand the sequence of execution between the microtask queue and task queue. Thank you!
Well explained with smooth & meaningful animation.
Awesome 👏👍
This channel is a precious gem! Thank you, Lydia. I know it takes a lot of effort, but I hope you could make more videos with excellent visual explanations like this.
Best example of a task queue I have seen in a very long time.
It is insane how much information you you were able to convey in one short video, I knew async tasks were pushed off to be filled later but I had no mental model how that worked until now.
I can't believe, there is literally not one incorrect word here. Amazing.
This video deserves 10M views. Incredible work Lydia!
This video is absolutely amazing! Very clear and straight to the point. I often struggle with understanding JS, and I found this video incredibly helpful. Thanks, Lydia! Looking forward for your new videos 👍
Thank you for all the efforts with the graphics!.. very well explained!! 👍👍
The presentation quality is top-notch! This is probably the best JS "under-the-hood" explainer out there
Just wow! This is pants down the best Tutorial-Style-Vid I have ever seen. Please keep it up, I love it!
No BS just pure content! True GEM!!
Subscribed right away at 4:22
These small concepts took me a long time to grasp while working with JS over the years