Joe Liccini

Why Your Cached JavaScript Is Still Slow and Incurs Performance Overhead

Screenshot of “Why Your Cached JavaScript Is Still Slow and Incurs Performance Overhead”

https://www.webperf.tips/tip/cached-js-misconceptions/

Most developers still don't understand that large JavaScript code is really hurting performance, let's hope this great explanation by Joe, that this is really not just about network, will help:

even if a web application has all assets optimally delivered and/or cached, that doesn't mean that it will run fast or render quickly when it is needed during runtime on the end-user's device.

  1. screenshot of Why We're Breaking Up with CSS-in-JS

    Sam Magura

    Why We're Breaking Up with CSS-in-JS

    Thanks for reading this deep dive into runtime CSS-in-JS. Like any technology, it has its pros and cons. Ultimately, it's up to you as a developer to evaluate these pros and cons and then make an informed decision about whether the technology is right for your use case. For us at Spot, the runtime performance cost of Emotion far outweighed the DX benefits, especially when you consider that the alternative of Sass Modules + utility classes still has a good DX while providing vastly superior performance.

  3. screenshot of Speeding Up Async Snippets

    Harry Roberts avatar Harry Roberts

    Speeding Up Async Snippets

    For all the resulting script is asynchronous, the <script> block that creates it is fully synchronous, which means that the discovery of the script is governed by any and all synchronous work that happens before it, whether that’s other synchronous JS, HTML, or even CSS. Effectively, we’ve hidden the file from the browser until the very last moment, which means we’re completely failing to take advantage of one of the browser’s most elegant internals… the Preload Scanner.

  5. screenshot of Hydration is Pure Overhead

    Miško Hevery avatar Miško Hevery

    Hydration is Pure Overhead

    The re-execution of code on the client that the server already executed as part of SSR/SSG is what makes hydration pure overhead: that is, a duplication of work by the client that the server already did. The framework could have avoided the cost by transferring information from the server to the client, but instead, it threw the information away.