GitHub - WICG/compression-dictionary-transport
This proposal adds support for using designated previous responses as an external dictionary for HTTP responses for compression schemes that support external dictionaries (e.g. Brotli and Zstandard). HTTP Content-Encoding is extended with new encoding types and support for allowing responses to be used as dictionaries for future requests. All actual header values and names still TBD: Server respon
Speeding up the JavaScript ecosystem - eslint
We've talked quite a bit about linting in the past two posts of this series, so I thought it's time to give eslint the proper limelight it deserves. Overall eslint is so flexible, that you can even swap out the parser for a completely different one. That's not a rare scenario either as with the rise of JSX and TypeScript that is frequently done. Enriched by a healthy ecosystem of plugins and prese
Perfetto UI
Perfetto UI - An unrecoverable problem occurred If you are seeing this message, something went wrong while loading the UI. Please file a bug (details below) and try these remediation steps: * Force-reload the page with Ctrl+Shift+R (Mac: Meta+Shift+R) or Shift + click on the refresh button. * Clear all the site storage and caches and reload the page. * Clear the site data and caches from devtools,
The truth about CSS selector performance
If you’re a web developer, you may have already heard that some CSS selectors are faster than others. And you’re probably hoping to find a list of the better selectors to use in this article. Well, not quite. But bear with me, I promise that by the end, you’ll have learnt something new about CSS selector performance. A quick look behind the scenes The way you write CSS selectors does play a role i
My talk on CSS runtime performance
A few months ago, I gave a talk on CSS performance at performance.now in Amsterdam. The recording is available online: (You can also read the slides.) This is one of my favorite talks I’ve ever given. It was the product of months (honestly, years) of research, prompted by a couple questions: What is the fastest way to implement scoped styles? (Surprisingly few people seem to ask this question.) Do
Introducing historical web performance data via the CrUX History API - Chrome Developers
Introducing historical web performance data via the CrUX History API Published on Tuesday, February 7, 2023 This article introduces the Chrome UX Report (CrUX) History API endpoint, which provides time series of web performance data. This data updates weekly, and allows you to see about 6 months worth of history, with 25 data points spaced out by a week. When used with the daily updates from the o
Speculation Rules API によるプリレンダリングのためのメトリクス設計
本記事では Speculation Rules API を使ったプリレンダリングの性能評価を行うためのメトリクスについて紹介します。 はじめに ウェブページの読み込みは本質的に時間のかかる処理です。ウェブブラウザは HTML ファイルを解析することでページ表示に必要なリソースを特定・収集・処理し、それらを組み合わせてページの描画（レンダリング）を行います。 ページ読み込みを高速化するアプローチの一つとして投機実行が知られています。投機実行はページ読み込みに必要な処理をあらかじめ実行しておくことで、実際にページを描画するときの処理を減らします。ウェブブラウザにはこのような投機実行を行うための API が多数実装されています。若干情報が古くなっていますが「リソースの読み込みを助けるウェブブラウザ API の世界」という記事に投機実行のための API をまとめたので詳しくはそちらを見てください。
What's new in Lighthouse 10 | Blog | Chrome for Developers
Lighthouse is a website auditing tool that helps developers with opportunities and diagnostics to improve the user experience of their sites. Lighthouse 10 is available immediately on the command line through npm and in Chrome Canary. It will land in Chrome stable in Chrome 112 and in PageSpeed Insights in the coming weeks. Scoring changes The venerable Time To Interactive (TTI) metric is being re
Performance of WebAssembly runtimes in 2023 | Frank DENIS random thoughts.
Using libsodium in a web browser has been possible since 2013, thanks to the excellent Emscripten project. Since then, WebAssembly was introduced. A more efficient way to run code not originally written in JavaScript in a web browser. And libsodium added first-class support for WebAssembly in 2017. On web browsers supporting it, in allowed contexts allowing it,this gave a nice speed boost. Like Ja
Optimize Time to First Byte
Time to First Byte (TTFB) is a foundational web performance metric that precedes every other meaningful user experience metric such as First Contentful Paint (FCP) and Largest Contentful Paint (LCP). This means that high TTFB values add time to the metrics that follow it. It's recommended that your server responds to navigation requests quickly enough so that the 75th percentile of users experienc
Why Not document.write()? – CSS Wizardry
If you’ve ever run a Lighthouse test before, there’s a high chance you’ve seen the audit Avoid document.write(): For users on slow connections, external scripts dynamically injected via `document.write()` can delay page load by tens of seconds. You may have also seen that there’s very little explanation as to why document.write() is so harmful. Well, the short answer is: From a purely performance-
Next.js製アプリケーションのコンパイルを約100倍高速化した話
Next.jsアプリケーションの開発時においてコンパイルが長時間に及ぶ問題が起きていたので、その原因を特定した手法と採用した解決策について記載します。 今回は結果的にコンパイル時間を100倍以上高速化することができました。 前提 今回の対応は以下のバージョンで行いました。 React@18.2.0 next@12.2.4 tailwindcss@3.2.4 postcss@8.4.14 Next.js の開発中に、コンパイル時間が長くなっていることに気づく 最近、Next.jsアプリケーションのローカル開発時に待ち時間が長くて生産性が低いのでなんとかしたい、という相談を受け、調査を開始しました。 まず、おもむろにyarn devでプロセスを立ち上げてみたところ、以下のようなコンパイル時間を示すログが表示されました。 yarn dev yarn run v1.22.19 $ next dev
The RUM Archive and Benford's Law
Amit Singh (@sans_colon) is a Senior Data Scientist at Akamai Technologies. He works on the mPulse team analyzing web performance data. The Akamai mPulse team studies Real User Monitoring (RUM) data to help our customers understand how to optimize website performance and how user behavior may be altered by changes to configurations or resource requests on their site. As a data scientist on the mPu
HTTP/3 Prioritization Demystified
Robin Marx is a Web Performance Architect at Akamai Technologies. His main expertise is in network protocol performance, including HTTP/3 and QUIC, which was the topic of his PhD research. In a previous life he was a multiplayer game programmer and co-founder of LuGus Studios. YouTube videos of Robin are either humoristic technical talks or him hitting other people with longswords. If you deal wit
103 Early Hints
Alex Hamer is software engineer at Tesco, with a passion for building high performance, accessible web applications for the many. For a dynamic web application Time To First Byte (TTFB) can take time, this is certainly the case with the applications I work with. For each request the server receives, in order to respond correctly it could be performing a number of things that can add up; multiple A
RUM Archive - Homepage
RUM Archive The RUM Archive is a publicly available and queryable dataset of anonymized Real User Monitoring (RUM) page loads and third-party resource fetches. Taking inspiration from projects like the Wayback Machine and the HTTP Archive, we aim to make RUM data freely available for researchers to analyze trends in market share and performance analytics. Want to query this data? Check out the doc
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deps: replace url parser with Ada by anonrig · Pull Request #46410 · nodejs/node
Why Is My Jest Suite So Slow?
LCP(FE)
Web Performance APIs Appreciation Post