How to Measure and Optimize React Performance | DebugBear Learn how to measure the performance of your React app and identify what's slowing it down.

How to Measure and Optimize React Performance

www.debugbear.com/blog/measuri...

Elena | Progressive Web Components Elena is a simple, tiny library for building Progressive Web Components.

I’m excited to announce the 1̶s̶t̶ 7th release candidate of Elena today! 🫶

Elena is a simple, tiny library for building Progressive Web Components. Unlike most web component libraries, Elena doesn’t force JavaScript for everything.

Crafted with love and care using HTML, CSS & plain JS: elenajs.com

“Progressive Web Components” title, author’s photo, three component type diagrams (Composite, Primitive, Declarative), and a terminal showing Elena CLI.

Progressive web components. Ariel Salminen introduces Elena, a 2.6 kB library for building web components that prioritize HTML and CSS, then hydrate with JavaScript. #webcomponents #js

arielsalminen.com/20...

Good luck 🇪🇺🇭🇺

MDN search for “Under the hood of MDN’s new frontend” with results for HTML, CSS, JavaScript performance optimization, Web APIs, and SVG over HTML source code. MDN logo in the corner.

Under the hood of MDN’s new frontend. @leo.mca.is explains how MDN replaced React with web components and Lit, using server components for static content and lazy-loading interactive islands. #mdn #webcomponents

developer.mozilla.or...

Ordering flex items

developer.mozilla.org/en-US/docs/W...

“What Is CSS Containment and How Can I Use It?” title, author’s photo, and OpenTable mobile site with DevTools showing contain: strict.

What is CSS containment and how can I use it? Harry Roberts covers each contain value, the content and strict shorthands, and content-visibility. Includes a real OpenTable case where containment cut layout time sixfold. #css #performance

csswizardry.com/2026...

una.im | Automated accessible text with contrast-color() Let the browser pick the most readable text color for any background with this new CSS function.

Automated Accessible Text With “contrast-color()”, by @una@front-end.social:

https://una.im/contrast-color

#css #functions #colors #contrast #accessibility

jonny (good kind) (@jonny@neuromatch.social) Attached: 1 image from @sushee@ohai.social [over here](https://ohai.social/@sushee/116325702070975973), (can't attach images in quotes) and apparently discussed on HN so i'm late, but... They REALLY...

Anthropic using regex instead of their actual *language model* to detect negative sentiment in prompts.

Supply Chain Attack on Axios Pulls Malicious Dependency from... A supply chain attack on Axios introduced a malicious dependency, plain-crypto-js@4.2.1, published minutes earlier and absent from the project’s GitHu...

🚨 Active supply chain attack on axios@1.14.1. The latest version pulls in plain-crypto-js@4.2.1 -- a brand-new package that didn't exist before today.

We're still investigating. If you use axios, pin your version and audit your lockfile. socket.dev/blog/axios-n...

Detail · Where craft lives A curated study of the tiny design decisions that make products feel exceptional in AI era. For designers and engineers who believe the small things can make big difference.

Detail: Small Interface Details That Make Big Difference - https://detail.design (Curated collection of tiny design decisions from real products. Good inspiration resource.)

The Practical Accessibility Course A get-right-down-to-it online course for Web designers and developers who want to start creating more accessible Web user interfaces and digital products today

Today I published the second update of this month to the Practical Accessibility course content.

I have at least two or three more updates coming this April.

As I promised, I want to keep the course as up-to-date and as relevant to your work as possible.

Get access @ practical-accessibility.today

Wikipedia now has higher standards than all universities

Anthropic's Claude Can Now Control Your Computer — CNET The developer is boosting Claude's agentic capabilities in an apparent effort to compete with platforms like OpenClaw.

If you give an LLM full access over your primary computer, I'd love to study your brain.

apple.news/Ay19QSmUuRTO...

I can't stress this enough, do not host client work on Vercel.

bsky.app/profile/konn...

Why Are We Still Doing This? Hi! If you like this piece and want to support my work, please subscribe to my premium newsletter. It’s $70 a year, or $7 a month, and in return you get a weekly newsletter that’s usually anywhere fro...

Free newsletter: Why're we still doing this? Despite $1tr+ in investment, every AI company is unprofitable, LLMs have yet to provide tangible productivity benefits, and private credit-backed data center debt may be the next great financial crisis.
www.wheresyoured.at/why-are-we-still-doing-this/

Code example showing the usage of Temporal.ZoneddateTime ```js // London DST starts: 2026-03-29 01:00 -> 02:00 const zdt = Temporal.ZonedDateTime.from( "2026-03-29T00:30:00+00:00[Europe/London]", ); console.log(zdt.toString()); // → "2026-03-29T00:30:00+00:00[Europe/London]" const plus1h = zdt.add({ hours: 1 }); console.log(plus1h.toString()); // "2026-03-29T02:30:00+01:00[Europe/London]" (01:30 doesn't exist) ```

Temporal is now Stage 4 at TC39 🎂🎂🎂

Thanks to all the other champions of JavaScript's new date-time API. It has been a wild ride over many years!

I wrote a blog post explaining how we got here 📜

bloomberg.github.io/js-blog/post...

JavaScript code snippet lists an inventory of items with names, types, and quantities, demonstrating `Object.groupBy()` functionality.

Stop writing reduce() just to group an array ✋

`Object.groupBy()` works on all major browsers, helping you group array elements by any key in one line.

Clean, readable, no dependencies.

Learn more 👇
developer.mozilla.org/en-US/docs/...

Gonna share this with my buddies 🙂

I started a new chapter of my Agentic Engineering Patternw guide about anti-patterns - things NOT to do

So far I only have one: Inflicting unreviewed code on collaborators, aka dumping a thousand line PR without even making sure it works first simonwillison.net/guides/agent...

How to use UUIDv7 in Python, Django and PostgreSQL Learn how to use UUIDv7 today with stable releases of Python 3.14, Django 5.2 and PostgreSQL 18. A step by step guide showing how to generate UUIDv7 in Python, store them in Django models, use Postgre...

How to use UUIDv7 in Python, #Django and PostgreSQL

www.paulox.net/2025/11/14/h...

Temporal - JavaScript | MDN The Temporal object enables date and time management in various scenarios, including built-in time zone and calendar representation, wall-clock time conversions, arithmetics, formatting, and more. It is designed as a full replacement for the Date object.

JavaScript's date object has been tricky for years, but that is changing.

The NEW Temporal API brings,
🌍 Easily handle time zones
📆 Precise date math
🕒 Parse ISO strings without errors
⌛ Durations, date ranges, and more.

Start experimenting 👇
developer.mozilla.org/en-US/docs/...

CSS shape() landed in Firefox 148. It's similar to path(), but allows the full expressiveness of CSS…

Goodbye innerHTML, Hello setHTML: Stronger XSS Protection in Firefox 148 – Mozilla Hacks - the Web developer blog Cross-site scripting (XSS) remains one of the most prevalent vulnerabilities on the web. The new standardized Sanitizer API provides a straightforward way for web developers to sanitize untrusted HTML...

Goodbye innerHTML, Hello setHTML: Stronger XSS Protection in Firefox 148

hacks.mozilla.org/2026/02/good...

Modern CSS Code Snippets | modern.css A collection of modern CSS code snippets. Every old CSS hack next to its clean, native replacement, side by side.

Stop writing CSS like it's 2015

modern-css.com

I've been seeing more mania surrounding Claude and OpenClaw these past 2-3 weeks, and it just reminds me that all useful technological advancements since the beginnings of mathematics are based on predictable behaviours and repeatability.
I'll take a look again when it has those two attributes.

JS-heavy approaches are not compatible with long-term performance goals

sgom.es/posts/2026-0...

Django Packages : Reusable apps, sites and tools directory for Django Django Packages stores information on fetched packages and provides easy comparison tools for them. Public APIs include PyPI, GitHub, and Bitbucket.

Django Packages is a directory of reusable apps, sites, tools, and more for your Django projects

djangopackages.org

#django

Visualize Django URL routing inside the Django Admin, including patterns, views, namespaces, and conflicts

github.com/yassi/dj-url...

#django