Browserslist now supports Baseline | Blog | web.dev
Published: September 16, 2025 Browserslist is a utility that tells build toolchains how to modify source code for a specified set of browsers. Browserslist relies on a query syntax that specifies exact versions of browsers, relative queries such as last 2 years, and even usage-based queries like > 0.5%. It's used by other popular tools such as Babel and PostCSS. Chances are, if you use any kind of
Storybook をフル活用してテストを実装したその後の話 - Cybozu Inside Out | サイボウズエンジニアのブログ
この記事は、CYBOZU SUMMER BLOG FES '24 (Frontend stage) DAY13 の記事です。 こんにちは、フロリアでエンジニアとして活動している hacchan です。 現在 kintone ではフロリアというプロジェクトの中で、Closure Tools から React への移行作業に取り組んでいます。 以前、そのフロリアのチームの 1 つである Reactone チーム が Storybook をフル活用してテストを実装した話 を紹介しましたが、今回はそのアフターストーリーを紹介します。 Storybook のフル活用はやめた 以前の Reactone チームでは、Storybook の Test Runner を使って、Integration Test を実行するなど、Storybook をフル活用してテストを実装していましたが、新たな領域の刷新を開
Testing The Swag Store Cypress.io Course
A couple of months ago I have announced a Cypress.io course Testing The Swag Store targeted at the beginners who want to learn web end-to-end and component testing using Cypress.io test runner. The short announcement video can be seen below It is hard to believe, but I have been on a roll creating lots and lots of lessons for this course. It now covers end-to-end testing, React component testing,
The origin private file system | Articles | web.dev
Motivation When you think of files on your computer, you probably think about a file hierarchy: files organized in folders that you can explore with your operating system's file explorer. For example, on Windows, for a user called Tom, their To Do list might live in C:\Users\Tom\Documents\ToDo.txt. In this example, ToDo.txt is the filename, and Users, Tom, and Documents are folder names. `C:` on W
Ladybird: A new cross-platform browser project
This post describes the Ladybird browser, based on the LibWeb and LibJS engines from SerenityOS. Since starting the SerenityOS project in 2018, my goal has been “to build a complete desktop operating system to eventually use as my daily driver”. What started as a little therapy project for myself has blossomed into a huge OSS community with hundreds of people working on it all over the world. We’v
Optimize long tasks | Articles | web.dev
Published: September 30, 2022, Last updated: December 19, 2024 Common advice for keeping JavaScript apps fast tends to boil down to the following advice: "Don't block the main thread." "Break up your long tasks." This is great advice, but what work does it involve? Shipping less JavaScript is good, but does that automatically equate to more responsive user interfaces? Maybe, but maybe not. To unde
Generating an EPUB File in the Browser
I’ve been meaning to blog about a few aspects of how I built my tool Readlists and I finally have the time to do it. So here we go. Readlists is a purely client-side app, i.e. JavaScript required. That’s something I might change in the future as I dabble in how to host and maintain a website with a server, but for now purely client-side is the way it works (because that’s the way I knew how to bui
Things not available when someone blocks all cookies
l'occasion f — Gelegenheit f, die ~ , der ~. bei Gelegenheit — à l'occasionI #StandWithUkraine 🇺🇦. The other day, I received a harmless-looking Issue for my app SVGcode (announcement blog post). The Issue read: Crash when opened with cookies blocked Hey I block cookies by default. Unfortunately your website doesn’t handle that nicely despite it not needing (IMO) cookies to operate. I'm getting t
ブラウザバック時の表示を最適化する Yahoo!ニュースの取り組み事例
ヤフー株式会社は、2023年10月1日にLINEヤフー株式会社になりました。LINEヤフー株式会社の新しいブログはこちらです。LINEヤフー Tech Blog こんにちは。Yahoo!ニュース を担当しているエンジニアの喜楽です。 今回は、Yahoo!ニュースが取り組んでいるブラウザバック時の表示最適化手法について紹介します。 なぜブラウザバック時の挙動に注目するのか ユーザーがYahoo!ニュースのページを閲覧し、別のページに遷移する方法は大きく分けて以下の2つが考えられます。 （A） リンクをたどってページを遷移する （B） ブラウザーのナビゲーションボタンまたはスワイプ操作によって遷移する 「戻る」による遷移（ブラウザバック） 「進む」による遷移（ブラウザフォワード） Yahoo!ニュースでは総PVのうち一定程度が(B)のブラウザバックまたはブラウザフォワードによるページ遷移時のも
How to Eliminate Render-Blocking Resources: a Deep Dive
You might be here because Lighthouse told you to "eliminate render-blocking resources". Render-blocking resources are a common hurdle to rendering your page faster. They impact your Web Vitals which now impact your SEO. Slow render times also frustrate your users and can cause them to abandon your page. I worked with one client to reduce their render-blocking resources and improved their site load
Cypress vs Selenium vs Playwright vs Puppeteer: Speed
Table of contentsWhy compare these automation tools?Methodology, or how we ran the benchmarkThe resultsConclusionOur recent speed comparison of major headless browser automation tools, namely Puppeteer, Playwright and WebDriverIO with DevTools and Selenium, received a very positive response. The single most common ask from our readers was that we follow up by including Cypress in our benchmark. In
The Cost of Javascript Frameworks - Web Performance Consulting | TimKadlec.com
There is no faster (pun intended) way to slow down a site than to use a bunch of JavaScript. The thing about JavaScript is you end up paying a performance tax no less than four times: The cost of downloading the file on the network The cost of parsing and compiling the uncompressed file once downloaded The cost of executing the JavaScript The memory cost The combination is very expensive. And we a
Is postMessage slow? — surma.dev
Toggle dark mode No, not really. (It depends.) What does “slow” mean? I said it before, and I will say it again: If you didn’t measure it, it is not slow, and even if you measure it, the numbers are meaningless without context. That being said, the fact that people will not even consider adopting Web Workers because of their concerns about the performance of postMessage(), means that this is worth
アメブロ2019: こえのブログでのPWA | CyberAgent Developers Blog
こえのブログは「声で書くブログ、声で聴くブログ、声で観るブログ」をコンセプトに書き手、読み手双方にバージョンアップしたブログを提供するアメブロの新機能です。 投稿者は端末に向かって喋るだけで、その音声が活字化されブログとして公開できます。閲覧者は活字化された文字を通常のブログと同じように読めるほか、音声を聴きながらでもコンテンツ消費できます。 モバイル端末、テレビ端末やスマートスピーカーなどの普及により、今後ますます増えると予想される利用形態に対して、それぞれに適した形でコンテンツを提供できるように挑戦しています。 この記事では、技術的な側面を中心にこえのブログを紹介します。 こえのブログは、文字でも音声でもコンテンツ消費できるのが特徴です。読者の方へのメッセージや質問に回答など利用法は様々です。龍玄としさんやクロちゃんさんなど著名人の方の声も聴けます。 できる限りサーバーにアクセスしない
JavaScript Loading Priorities in Chrome
February 18, 2019 How browsers schedule and execute scripts can impact the performance of web pages. While techniques like <script defer>, <link rel=preload> (and others) influence script loading, knowing how browsers interpret them can also be helpful. Thanks to Kouhei Ueno, we now have an up to date summary of script scheduling in Chrome.
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Compression Streams are now supported on all browsers | Blog | web.dev
Protractor Deprecation Update August 2023
Scrollend, a new JavaScript event | Blog | Chrome for Developers
Web Performance APIs Appreciation Post
(PDF) COSMICDUKE Cosmu with a twist of MiniDuke - F-Secure
