fidzu : javascript

#​804 - September 29, 2026

Read on the Web

JavaScript Weekly

How Anthropic Made Claude's Apps 3x Faster in Two Weeks - A grab bag of performance lessons from a sprint that cut p75 'time-to-typeable' from 3.1s to 0.55s. Em dashes (the irony!) pushed V8 onto a slower regex path, a stray location.reload() caused half a million hidden reloads a day, and more.

Wang, Attard, and G (Anthropic)

Still Writing Tests? Meticulous Is Here - Notion, Dropbox and Wiz are now using a testing paradigm they can't ship without. Built by former Palantir engineers, Meticulous creates an evolving suite of deterministic E2E UI tests, delivering exhaustive coverage with zero developer effort.

Meticulous AI sponsor

Vite+ 1.0: One CLI for Your Entire JavaScript Toolchain - The single vp command can now manage your Node runtime (if you wish), package manager, dev server, linting, formatting, testing, builds and task running, configured from vite.config.ts. vp migrate can be used to bring existing Vite, Vitest, ESLint, tsup, and similar setups into Vite+.

VoidZero

💡 Evan You also looks back at four months of VoidZero at Cloudflare, including work on the Oxc React Compiler, Vitest 5, stable type-aware linting, and more.

IN BRIEF:

• The latest TC39 meeting is taking place in Tokyo now, and three iterator proposals have already advanced to stage 4: chunking, join and includes (the latter just shipped in Chrome 154).

• Jarred Sumner shared 𝕏 a preview of Bun compiling JavaScript ahead of time: 24% faster startup and 48% less memory for Claude Code, but ~2x binary size.

• 🎉 Cloudflare finally has a single CLI for all of its APIs. cf is written in TypeScript and covers everything, whereas Wrangler only ever covered a subset.

• The Angular team is building a partly Rust-powered compiler, because TypeScript 7's Go port lacks APIs the current one relies on.

RELEASES:

• MSW (Mock Service Worker) 3.0 - The popular API mocking library is now ESM-only, adds a Vite plugin, supports GraphQL subscriptions, and can intercept page navigations and form submissions.

• Vinext 1.0 - Cloudflare's Vite-based Next.js reimplementation now supports the Pages and App Routers, and offers a migration path for existing apps.

• Mermaid 12.0 - The diagramming tool now defaults to the ELK layout engine for flowchart, class, state and similar diagrams, so existing ones will look different unless you set layout: dagre. Also adds UML use case diagrams.

• pnpm 12.8, Angular 22.2, TinyBase 10, QUnit 3.0

📖 Articles and Videos

The Grand Unifying Architecture of Frontend - SolidJS's creator argues that HTMX, React, LiveView, and friends differ mostly in how they split the same three jobs (navigation, content, and instant UI feedback) between client and server. He then shows how Solid 2.0 aims to cover the whole spectrum.

Ryan Carniato

Build Products That Help People Build Their Lives - Fidelity technologists can change the way our clients invest - for the better and for everyone.

Fidelity Careers sponsor

Optimizing Objects with null Prototypes - In V8, objects created with { __proto__: null } or Object.create(null) start in a slower 'dictionary mode'. Matteo shows how creating a plain object and then setting its prototype to null preserves fast properties.

Matteo Collina

💡 If you fancy going deeper, Fast properties in V8 is the V8 team's 2017 explainer of how objects switch between fast and 'dictionary' mode.

Node.js Built-ins That Replace npm Packages - A tour of 12 Node built-ins that replace common ecosystem packages along with their stability levels and some gotchas that might keep you using the established alternatives.

Flavio Copes

📄 JavaScript's Greatest Pun? ${{ }} - Looks like Mustache, but ${{ name }} passes an object using shorthand properties to a tag function, preserving both the variable's name and value. Nishant Shukla

📄 How GitHub Improved Performance by Moving Off CSS-in-JS Josh Black and Marie Lucca (GitHub)

🛠 Code & Tools

Size Limit: A JavaScript Performance Budgeting Tool - Set a size or load-time budget for your code and this tool can fail CI (or flag a PR) if a change goes over it. You can also do one-off checks and see visualizations of where the bytes are. Framework-agnostic and doesn't care which bundler or CI you use.

Andrey Sitnik

Your UI Gets Blamed for a Slow Query - TimescaleDB extends Postgres so the query behind your UI returns fast as data grows. Get $1000 credit to start.

Tiger Data (creators of TimescaleDB) sponsor

EmDash 1.0: Cloudflare's WordPress 'Successor' is Now Stable - An Astro-based alternative to WordPress, now with a decentralized AT Protocol-based plugin registry and plugins that run in sandboxes. It's not Cloudflare-only, either, as it also runs on Node.js.

Buscemi, Kane, and Pham (Cloudflare)

📝 DOCX 9.8: Generate Word .docx Files from JavaScript - A comprehensive library for generating docx files. It's only a few months since we linked to it, but this is a big release with support for charts, shapes and watermarks, plus more math notation support. (Homepage.)

Dolan Miu

• 🔊 wavesurfer 8.0 - Popular audio waveform renderer and player. Refactored for better efficiency, with numerous bug fixes.

• pretty-bytes 7.2 - Convert byte quantities into human readable strings.

• ✉️ postal-mime 4.0 - An email parsing library that works everywhere.

• Typia 15.0 - Turn pure TypeScript types into runtime validators.

📢 Elsewhere in the ecosystem

• 🎵 Tonny Espeset has recreated the '80s hit Take on Me by A-ha in pure JavaScript (along with synthesized vocals!), running through the always-entertaining Dittytoy online JavaScript music playground.

• Git 2.56 has just been released. It adds git add --resolved to safely stage merge conflict fixes, git branch --delete-merged for bulk branch cleanup, and more. All explained within.

• TanStack's Tanner Linsley built Redact, 'an alternative logical projection of React' aiming for full API compatibility with a simpler implementation, smaller bundles and better performance. It's now on GitHub.

• A quick history of why certain port numbers like 3000 and 8080 are commonly used in development.

#​803 - September 22, 2026

Read on the Web

JavaScript Weekly

tinyjs: Build JavaScript Desktop Apps in <10MB - I built an app with this and was impressed. You get a txiki.js-powered backend with full system access (including FFI!), native webview rendering, and tiny macOS, Linux, and Windows builds. It even makes it easy to sign/notarize the final app.

Tarwin Stroh-Spijer

There are lots of great options in this space though:

• Electrobun offers richer multi-window and GPU features, at the cost of a larger TypeScript runtime - though it can instead use Zig, Rust, Go, or Odin for a tiny native main process.

• Perry is a TypeScript to native AOT compiler whose primary UI model renders AppKit, Win32 and GTK4 widgets for a more conventionally native feel.

• Electron and the experimental Deno Desktop are powerful, but their executables typically run several times larger.

• Neutralinojs apps can be even smaller than tinyjs's, but you lose the general-purpose JavaScript privileged backend by design.

Full-Text Search in Drizzle Without a Second System - Try the official ParadeDB integration for Drizzle. Search your live Postgres tables. No ETL, no Elasticsearch. ParadeDB cloud coming soon.

ParadeDB sponsor

Persistent Databases in the Browser with DuckDB-Wasm and OPFS - A walkthrough of running DuckDB in the browser with a database file that survives reloads using the Origin Private File System now supported by all major browsers.

Piovesan and Wielenga (DuckDB)

How Linear Reworked Its CI for 4x the Tests - Eager agents grew Linear's test suite, and its CI costs with it! They share some remedies: rewriting type-aware ESLint rules as plain AST checks cut lint time 55% and eased a move to Oxlint, while selectively turning off Vitest's isolation saved a further 17% a month.

Mufeez Amjad (Linear)

IN BRIEF:

• Lovable rewrote Vite's dev server in Rust (calling it OJ) for performance reasons, but Evan You disputes the benchmark and predicts AI will have everyone maintaining "their own slop fork".

• 📊 npmchart.com plots download trends, releases and repo activity for any npm package (here's Svelte's, for example), and lets you compare packages.

• 🔒 npm now offers stage-only tokens to let automated workflows stage a release for a maintainer to approve with 2FA. This offers a migration path for those who can't move to trusted publishing yet.

RELEASES:

• Turborepo 2.11 - Experimental Rust, Python and Go support joins the task graph, plus up to 4x faster startup over 2.9.

• ESLint 10.11.0 - Performance update with faster startup and linting.

• Node.js 26.10.0 (Current) - Adds util.debounce/throttle.

• 📊 billboard.js 4.1, QuickJS-ng 0.17.0, VueUse 15.0

📖 Articles and Videos

An Undercover Analyst Infiltrated the Gang Behind 'Mini Shai-Hulud' - Bad news for the group behind this spring's cascading supply chain attacks… Google had a mole in their group chat! WIRED explains how the group was monitored and disrupted, leading to two recent arrests.

Andy Greenberg (WIRED)

The V8 Runtime Undermined My Constant-Time JavaScript Library - A look at how even branchless JavaScript can leak secrets through CPU cache behavior, due to quirks in how V8 handles booleans and -0.

Soatok Dreamseeker

Your UI Isn't Slow. It's Waiting on the Data - TimescaleDB extends Postgres so the data behind your UI loads fast as it grows. Get $1000 credit to start.

Tiger Data (creators of TimescaleDB) sponsor

Do Frameworks Matter Anymore? - If you're using AI, you're either using a framework or your agent is building an ad-hoc one on the fly. A Remix team member argues that's a good reason to want frameworks, and better ones, too.

Brooks Lybrand

📄 We Are All Product Engineers Now - Laurie argues that understanding what customers need becomes a core developer skill. Laurie Voss

📺 Is AI Changing How JavaScript Itself Gets Designed? - A 2-minute take from TC39 delegate Michael Ficarra. JetBrains

📄 Solid 2.0: It's the Little Things - Six touches that change how SolidJS 2.0 feels. Brenley Dueck

📄 How Notion Handles Concurrent Editing with CRDTs Nehmzow and Guo (Notion)

🛠 Code & Tools

Plotly.js 4: A Big Update for the Popular Charting Library - Now ships its own TypeScript types, adds 'quiver' plots (above) for drawing vector fields (with many awesome examples in the post), accepts CSS Color 4 color strings, and removes Mapbox GL in favor of MapLibre (no token needed!)

Chris Parmer

🤖 Transformers.js v4.3: Run AI Models in the Browser - Adds support for structured output (e.g. JSON), using WebGPU on Safari 26+, and DeepSeek v4. The docs have had an overhaul and there's now an agent skill you can use.

Hugging Face

💡 Hugging Face also released a collection of 207 Apache-2.0 WebGPU kernels - matmul, attention and quantization ops for your own runtime.

Still Writing Tests Manually? Meticulous AI Is Here - Flaky tests slowing down dev? Meticulous gives engineers confidence to ship faster by autonomously testing every edge case of your web app.

Meticulous sponsor

@shadcn/lint: An Agent-First Linter for Tailwind - An ESLint/Oxlint plugin to enforce rules like "no raw colors" and "no restyling <Button> from outside" with errors to steer agents back to your variants and tokens.

shadcn

Devframe: A Framework for Building DevTools That Run Anywhere - From the developer behind Vitest and Nuxt DevTools, "a framework for building DevTools, in the same way Nuxt or Next.js provides a framework [for web apps]". Define a tool once and Devframe turns it into a Web Standard request handler you can mount almost anywhere.

Anthony Fu

✉️ Mailflare: A Self-Hosted Inbox Built Entirely on Cloudflare - A self-hosted inbox for custom domains built on Cloudflare's Email Routing, Workers, D1 and R2. AGPL 3.0 licensed.

Hieu Nguyen

• gridstack.js 14.0 - The popular drag-and-drop dashboard layout library adds a list mode that reflows widgets like a reorderable list. (Demos.)

• 🖼️ image-dimensions 2.6 - Quickly get an image's dimensions by reading the least amount of data.

• Feedsmith 3.0 - A fast way to parse and generate web feeds, including RSS, Atom, and JSON.

📢 Elsewhere in the ecosystem

• I love these pure CSS 'hand drawn' annotations (above) you can add to any page in a data-note attribute.

• Cloudflare's Sunil Pai writes about the senior engineer 'death spiral', where you go dark for weeks to prove yourself in a new role and end up burning out.

• 🤖 Simon Willison writes about Jev, a new, fast 'decision model' taking developer social media by storm. Feed it semi-structured state and one or more questions and you get only numbers back (probabilities, choices and scores).

• GitHub Actions has a new cache-mode setting to limit cache access per workflow or job, a defence against the kind of cache poisoning that compromised TanStack's npm packages in May.

#​802 - September 15, 2026

Read on the Web

JavaScript Weekly

Functional Programming Jargon, Mapped and Explained - Currying, purity, functors, monads…? If FP terms ever go over your head, TC39 delegate Hemanth HM's popular jargon reference is now an explorable map of concepts showing how they relate, each with a simple definition and JavaScript example.

Hemanth HM

Stay Sharp in the Age of AI - Master.dev instructors build at Anthropic, OpenAI, Netflix, Google, and Stripe. Learn from them with hundreds of courses, live workshops, and expanded AI learning paths. New members get $100 off a yearly membership.

Master.dev sponsor

Modern Web Types: TypeScript Support for Newer Web APIs - TypeScript's DOM types only include APIs shipped in multiple browser engines, so things like element-scoped startViewTransition and fetchLater throw up errors. modern-web-types is a drop-in lib.dom replacement that adds missing interfaces/members shipped in any single browser engine.

Philip Walton (Google)

React 19.3 Released - A significant minor release making view transitions and Fragment Refs stable, adding Trusted Types support, and more. We covered it in more depth in last week's React Status.

The React Team

IN BRIEF:

• 🔒 Attackers are scanning for exposed Vite dev servers exploiting a server.fs.deny bypass (patched in Vite 7.3.2 and 8.0.5 earlier this year) to grab credentials from .env files. Vite listens on localhost by default, but double check your setup.

• Safari 27 shipped yesterday (alongside macOS/iOS 27), bringing the module loader rewrite we covered last week, so top-level await now works reliably in all major browsers.

• TC39 meets in Tokyo in two weeks. Here's the agenda with three iterator helper follow-ups (join, includes and chunking) all up for Stage 4, plus more.

• 🔒 Starting this Thursday, the OpenJS Foundation's CVE team is taking a break till October 6 due to burnout driven by a surge of AI-generated reports. Actively exploited issues will still get a response.

• 🔒 npm now places a temporary 72-hour 'security hold' on any account after a successful recovery-code sign-in.

RELEASES:

• pnpm 12.4 - The package manager can now manage Rust crates and Python packages alongside npm ones in a single workspace.

• Playwright 1.63 - Tests can now declare a named lock so those sharing a resource never run concurrently.

• Node.js v26.8.2 (Current) and v24.21.0 (LTS) - Both include a security release of Undici to fix numerous vulnerabilities.

• React Router 8.4, Vite 8.3, Moment.js 2.31.0 (security release).

📖 Articles and Videos

A Design Space Exploration of async/await - A simple async/await example produces different results in JavaScript, Rust, Python and Swift. Test your mental model with a quiz, then learn about the design choices behind the differences.

Gavin Gray

Native is Now the Future of Mobile at Shopify - Shopify is rewriting its React Native mobile apps in Swift/Kotlin. The main argument is coding agents have cut the cost of writing everything twice, while the upsides of native remain.

Mustafa Ali (Shopify)

Workshop: From an Error to the Logs That Explain It - Reading logs next to traces and errors, holding context across services, and cutting the noise.

Sentry sponsor

A Deep Dive into StyleX - A hands-on tour of Meta's StyleX, which turns JavaScript style objects into plain atomic CSS at build time, and why it can be a good fit for coding agents in particular.

Flavio Copes

📄 'Nobody Pays for Open Source: We Can Force Them To' - Laurie Voss ran npm for five years and thinks registries are an untapped lever for funding maintainers. Laurie Voss

📄 Anecdotally, Programmers Dislike reduce - map and filter sail through code review, but reduce draws complaints. Evan has a few theories why. Evan Hahn

🛠 Code & Tools

SnapDOM 3.0: Turn DOM Elements Into Images, Canvas and More - Zero-dependency html2canvas alternative with support for pseudo-elements and Shadow DOM. v3.0 adds 'incremental recapture' for faster repeat captures, automatic web font embedding, and fromString() for turning raw HTML markup into images.

Zumerlab

Your App Didn't Get Slower. Your Data Got Bigger - TimescaleDB extends Postgres so queries stay fast at scale, even as your data grows. Get $1000 credit to start.

Tiger Data (creators of TimescaleDB) sponsor

Fallow: Codebase Intelligence for TypeScript and JavaScript - A fast, zero-config Rust binary that finds dead code, duplication, circular dependencies and complexity hotspots in JS/TS projects. It's also pitched as a deterministic check for AI agent coding loops. GitHub repo.

Bart Waardenburg

🎨 category-colors: Generate 'Least Wrong' Color Palettes for Charts - Matt devised this algorithm for picking categorical chart colors in 2022 while design director at Stripe. It's now available as an npm package, and you can try it out on the Web here.

Matt Ström-Awn

• React DevTools 8.0 (Chrome Web Store) - The Suspense tab is now on by default, the Timeline profiler is gone (use your browser's Performance panel instead), and inspecting a DOM node now shows its matching React component.

• Zod 4.6 - Adds .validate(), a boolean check that skips building errors and is up to 35x faster than .safeParse().success on invalid input with compiled schemas.

• Javet 6.0 - Embed Node.js v26's runtime in the JVM for full interop with Java.

• parse-xml 5.0 - The fast, compliant XML parser goes ESM-only.

• 🕹️ n64js 1.0 - A Nintendo 64 emulator in pure JavaScript.

📢 Elsewhere in the ecosystem

• 🕹️ This year's js13kGames entries are in with a record 317 games squeezed into 13KB each. Frank Force's SP13KTRA racer and the Hornbound roguelike are good places to start, and you can dig around the public repos of every project too.

• Chris Coyier rounds up new and emerging HTML features worth knowing about, like the <geolocation> and <install> elements, as well as HTML-in-Canvas and improvements to <select> customization.

• The first Three.js Conference took place in Paris last week, and Codrops has a live-blog writeup of both days, including Mr.doob's talk. No recordings yet.

• Tailwind Labs, the team behind Tailwind CSS, is joining Shopify. Tailwind CSS is to remain maintained and open source - phew! 😅