Hasty Treat - JavaScript Event Buzzwords — Sync, Concurrent, Defer, Blocking, Workers

In this Hasty Treat, Scott and Wes define some JavaScript Buzzwords and talk about what they mean! Freshbooks - Sponsor Get a 30 day free trial of Freshbooks at freshbooks.com/syntax and put SYNTAX in the “How did you hear about us?” section. Sentry - Sponsor If you want to know what’s happening with your code, track errors and monitor performance with Sentry. Sentry’s Application Monitoring platform helps developers see performance issues, fix errors faster, and optimize their code health. Cut your time on error resolution from hours to minutes. It works with any language and integrates with dozens of other services. Syntax listeners new to Sentry can get two months for free by visiting Sentry.io and using the coupon code TASTYTREAT during sign up. Show Notes 03:24 - Synchronous / Async 05:23 - Multi-threaded JavaScript has a single “main thread” But you can have more threads with web workers 08:12 - Blocking JavaScript can stop other things on the page from running A script tag can block HTML from being parsed Most stuff in JavaScript is non-blocking Node.js write to filesystem can be blocking 10:27 - Concurrent + Parallel JavaScript start/stop are concurrent The API runs on a different thread Doesn’t REALLY matter https://joearms.github.io/published/2013-04-05-concurrent-and-parallel-programming.html

13:22 - Consecutive / Waterfall One after another 13:48 - Callback A function to run when this thing happens or is done

Click event callback Websocket on data callback Like a tweet stream Data fetch callback Almost entirely replaced with async + await http://callbackhell.com/

https://caolan.github.io/async/v3/

17:56 - Script Tag Async + Defer Doesn’t block other content Runs when ready - doesn’t care about DOMcontentLoaded Wait until the page is loaded before running If the script tag is above content, don’t wait for it Good for things that aren’t called on page load 21:54 - Lazy Load it in later - maybe when it’s scrolled into view, or as needed Not mission-critical Tweet us your tasty treats! Scott’s Instagram

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