JSConf
7 HN recommenders · recommended in 8 months, 2018–2023
35:12 · 808K views · Feb 9, 2018
Jake Archibald's JSConf.Asia 2018 talk "In the Loop" explains the browser event loop, covering tasks, microtasks, requestAnimationFrame, and how rendering interleaves with JavaScript. It uses visual walkthroughs to show why code runs in surprising orders and why setTimeout fixes are unreliable.
HN treats it as the best primer on the event loop, praising its entertaining, easy-to-grasp visual explanations.
9 comments from Hacker News
The best primer for the event loop I have found is here: this video The speaker (Jake Archibald) has that rare ability to be both likeable and relatable, while also being incredibly knowledgeable and enthusiastic. I wish a lot more talks were like this!
Jake Archibald's "In the Loop", Visual explanation of how the javascript event loop works! Awesome video for every javascript developer. this video
Jake Archibald talking about the javascript event loop and actually making it both entertaining and easily grokable! this video
> It basically flickers between tasks very rapidly to simulate concurrency. That’s usually used a description of preemptive multitasking, like what you get running a modern OS on a single core (on multiple cores it’s also this but on each core). Every once in a small while, the current task is made to inhale chloroform, another task is chosen to wake and takes its place. Pro: you can’t hang any given task from a single thread; con: shared memory is very difficult to impossible, as you never know when you’ll be interrupted. Browser JavaScript and UI interactions instead use cooperative multitasking, which you’ll also find in classic Mac OS, 16-bit Windows, basically every embedded system ever, and languages like Python and Lua. A task has to explicitly call out to the scheduler to hand off execution resources to the next one. Pro: as task switching only happens at clearly visible points, many of the horrors of shared memory are diminished; con: you can and will hang the UI (or other outside-world interactions) if you accidentally write an infinite loop or just do too much CPU-bound work without yielding (as any developer using one of the aforementioned systems knows). For how this works in the browser environment specifically, see Jake Archbald’s superb talk[1]. [1] this video
I've been struggling with wrapping my head around asynchronous programming with callbacks, promises and async/await in JS, however I think it's finally clicking after watching these YouTube videos and creating a document where I explain these concepts as if I'm teaching them to someone else: * Philip Roberts's What the heck is the event loop anyway? - [LINK] * The Story of Asynchronous JavaScript - [LINK] * JavaScript Callbacks, Promises, and Async / Await Explained - [LINK] * Async Javascript Tutorial For Beginners (Callbacks, Promises, Async Await). - [LINK] * Jake Archibald: In The Loop - setTimeout, micro tasks, requestAnimationFrame, requestIdleCallback, - this video Edit... I've been rewatching these videos, reading the MDN docs, the Eloquent JavaScript book, javascript.info, blogs about the subject, etc. This further proves you shouldn't limit yourself to a single resource, and instead fill up the laguna with water from different sources if you will.