fidzu : JavaScript

#​799 - August 25, 2026

Read on the Web

🏖️ I'm back from an intense week of Disney vacationing with the family, so I feel more tired than before I left 😅… but it's time to catch up with all things JavaScript!
__
Your editor, Peter Cooper

JavaScript Weekly

Bun 1.4: Now More Node.js Compatible Than Ever - Several weeks after it was initially expected to launch, Bun's big AI-powered rewrite from Zig to Rust is here, complete with traditional ▶️ release video. A lot of effort has been put into compatibility, not just with Node, but Next.js, Playwright, Vitest, and Nuxt too. Throughput and CPU/memory usage also see huge improvements.

The Bun Team

☕ Grab the biggest coffee you can if you intend to get through the release post. It's easily the longest I've ever seen in fifteen years of running this newsletter.

Webflow for Developers - Most tools make you choose between visual builders and real code. Webflow gives you both: APIs, SDKs, Code Components, and Webflow Cloud to deploy custom apps, plus an MCP server to build with agents.

Webflow sponsor

🎵 Music Theory for JavaScript Developers - A from-first-principles tour of music theory, deriving the twelve notes, scales, chords and progressions from plain arithmetic, with runnable Web Audio examples throughout.

Luke Haas

Solid 2.0 RC: The Big <Reveal> - Async now lives in the reactive graph, so async data flows through ordinary memos. createResource, batch and startTransition are gone. SolidStart gets retired into a start: true flag on the Vite plugin, and the API is now frozen.

Ryan Carniato

IN BRIEF:

• Aurora Scharff shows off how Next.js 16.3 helps developers build 'app-like' experiences.

• Aviv Keller presents a recap of everything from Node.js Interactive 2026 which took place in Atlanta two weeks ago.

• 🤖 TanStack AI has entered its RC phase with a look at the journey so far and its main feature set.

• Oxlint has gained React Compiler support.

RELEASES:

• Electron 44 - No post yet, but it has dropped 32-bit support, requires macOS 13+, clipboard is now aligned with the W3C Clipboard API, and added net.WebSocket and the ability to set window opacity on Linux.

• Waku 1.0 RC - Minimal RSC-first React framework, now API-frozen ahead of v1 final, adding type-safe navigation that catches bad routes at compile time and experimental instant paints from cached route shells.

• SvelteKit 3 Release Candidate, React Native 0.87, ESLint 10.9 (and 10.9.1), Axios 1.20.0, pnpm 11.23

📖 Articles and Videos

The Wicked Reason Removing Code Beats Better Scheduling - A lot of performance work goes into shuffling when things load, when the bigger win is usually not sending the code at all. Alex Russell makes the case that this is a management problem more than a technical one.

Alex Russell

ESM and CommonJS: What import and require Actually Do - They look like the same operation, but Gabor shows how an ESM import stays wired to the exporter's binding, while a destructured require() only holds a copy. The consequences show up in circular dependencies and published packages.

Gabor Koos

Build with Strategy. Lead with Curiosity - Fidelity is looking for technologists that ask questions, challenge conventions and care about the impact of their products.

Fidelity Careers sponsor

How Cloudflare Moved Its Blog to Its Own WordPress Alternative - How Cloudflare moved its main blog onto EmDash, the Astro CMS it's building. Interesting parts include the k6 load tests and using a proxy Worker to ramp up traffic during switchover.

Jackson, Carneiro, and Dutton (Cloudflare)

📺 The Creator of TypeScript on 10x Faster TypeScript and Why AI Won't Replace SWEs - A candid hour-long interview with Microsoft's Anders Hejlsberg. Ryan Peterman

📄 Hiding Internal State in TypeScript Objects - How a non-exported unique symbol used as a property key keeps internal state out of Object.keys and JSON.stringify. Carlos Menezes

📄 Reliable Query Prefetching with TanStack Router Dominik Dorfmeister

📄 I Patched the TypeScript Compiler to Add Up Nine Numbers Hugo Vilela

🛠 Code & Tools

MicroLighter: A 2KB Syntax Highlighter That Doesn't Touch the DOM - A small, client-side syntax highlighter that makes use of the CSS Custom Highlights API. No dependencies, and with themes for light and dark modes. The homepage has some live demos.

Dave Rupert

TermDOM: Build Terminal UIs with HTML, CSS and DOM - A real DOM and layout engine to paint to the terminal, so you can write a TUI with vanilla JS (or framework of choice) and HTML (not just React, as with Ink). This week's v0.1.5 release adds CSS grid support.

Brian Kim

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 cluster.

ParadeDB sponsor

Formisch 1.0: Framework-Agnostic Schema-Based Form Library - A headless form library where a Valibot schema drives types and validation across eight frameworks. v1 adds Angular and React Native support, migration guides for TanStack Form/React Hook Form/Formik users, plus Markdown docs for agents.

Formisch Team

Stryker Mutator 10.0: Test Your Tests with Mutation Testing - Stryker makes small, deliberate changes to your code and checks whether your test suite catches them. If it doesn't, your tests may be too lax and need work. Here's how to get started.

Jansen, de Lang, et al.

• Ionic Framework v9 - The mobile-first UI toolkit for React, Angular and Vue returns after a two-year gap with React Router 6 support, zoneless change detection in Angular 21+, and more. There's an upgrade guide for v8 users.

• Papa Parse 5.7 - Fast, flexible CSV-to-JSON and JSON-to-CSV library.

• 🌐 MapLibre GL JS 6.6 - GPU-accelerated vector tile rendering library for interactive maps in the browser.

• 📊 Plotly.js 4.0 - Standalone library for creating interactive data visualizations.

• GTKX 1.3 - Create native GTK-powered Linux desktop apps with React.

• 📺 YouTube.js 18.0 - JavaScript client for YouTube's internal API.

📢 Elsewhere in the ecosystem

Some other interesting tidbits in the broader landscape:

• Last week the Next.js team did an AMA (Ask Me Anything) on Reddit and the thread is packed with answers and insights.

• 🖼️ Jake Archibald posts an update on Firefox's coming support for JPEG XL which Chrome is also planning to support soon.

• 📊 Gajus Kuizinas has put together a CSS-in-JS Arena comparing StyleX, Panda CSS and his own brand new Bamboo CSS on the same React Router 8 app.

• Did you know splitting a git commit is now a single command (in Git 2.54+)? git history split <ref> walks the change hunk by hunk and prompts for both messages.

• 🕹️ An N64 emulator written in JavaScript. If you have a ROM file to use, you can play with it here.

#​798 - August 11, 2026

Read on the Web

🏖️ A brief scheduling note: We're taking a summer break next week, so we'll be back in your inbox on August 25. Catch you then!
__
Your editor, Peter Cooper

JavaScript Weekly

Migrating a Large Flow Monorepo to TypeScript - Over several years, Yelp moved 1.4 million lines off Flow, and this writeup is more useful as a guide to running any long migration than as a Flow story. It was a big win on its own terms, with type coverage up from 83% to 96%.

Shawn Walton (Yelp)

💡 If you missed it, Yelp also wrote about its webpack to Rspack migration.

Render Runs JavaScript, Front to Back - Link your repo and Render takes it from there. Wire up your Vite site to your Hono API to your BullMQ job to your distributed agent workflow, all on one platform. Loop in your agent with official Render /plugins for Codex and Claude Code. Start free and scale from there.

Render sponsor

Kitesurf: Cloudflare's Agent-First Browser in V8 Isolates - A browser engine that runs on Workers with one isolate per page. Aimed at agents rather than humans, it uses 3-7x less CPU and memory than Chromium, at the cost of being slower. You can try it out now in beta, and it'll be open sourced in due course.

Martinho, Constant, Figueira, and Duarte (Cloudflare)

IN BRIEF:

• pnpm 12, the Rust rewrite, is now a release candidate, and only three things differ from pnpm 11.

• Bun 1.4 continues to be teased on 𝕏 on an almost daily basis, and is expected any day now, though creator Jarred Sumner has been distracted by trying to solve the Riemann hypothesis.

• 🔒 A 12-year-old weak PRNG in crypto-js was used to drain crypto wallets, though only if you generated secrets with it on a pre-4.0.0 (2020!) release.

RELEASES:

• Deno 2.9.5 - Adds an experimental QuickJS backend for deno compile and deno desktop.

• Node.js 26.7.0 (Current) - Adds --test-coverage-include-all, FFI and SQLite crash fixes, and initial support for Perfetto tracing.

• SolidStart v2 - SolidJS's equivalent of Next.js or SvelteKit.

• Preact 11 Release Candidate, Astro 7.2, Motion 13.1

📖 Articles and Videos

How Baseline Can Help You Ship Less JavaScript - A practical audit method for your dependencies. Groups them into clusters (Intl, HTTP, UI primitives, lodash), gives you questions to ask before deleting things, and works through a case where a swap can make your bundle bigger (Day.js → Temporal). A familiar theme developed into a rigorous, reusable audit.

Jad Joubran

Making More npm Packages Work with jsDelivr ESM Mode - jsDelivr is a popular CDN used to load npm packages into pages without a build step. This is a thorough, technical tour of what happens when converting packages to browser ESM (via its /+esm endpoint) and all the ways CommonJS finds to make that hard.

Martin Kolárik (jsDelivr)

Join Sentry Live: How Etsy Stays Crash-Free - Sentry and Etsy break down how they prep for peak traffic and debug in real time.

Sentry sponsor

Progressive Enhancement Inside of JavaScript - Working on a train, a patchy data connection got Remy to notice users can interact with a page before its JavaScript is ready, with a neat fix being to bind a handler early and replay the intent later.

Remy Sharp

📄 How the Astro Team Built a 'Software Factory' to Slash Its Issue Count - Agent-driven triage took Astro from over 200 open issues to 30. Matthew Phillips

📄 Debugging Stuck Node.js Processes - A trick for catching event loop blockers that never yield. Winona Schroeer-Smith

📺 Stop Reviewing Diffs. Start Reviewing Systems Kent C. Dodds

🛠 Code & Tools

celld: Durable Objects on Your Own S3 Bucket - A self-hosted take on Cloudflare's Workers and Durable Objects from Deno. V8 plus SQLite and Litestream's LTX coordinate through an S3 bucket with no consensus layer. GitHub repo.

Ryan Dahl (Deno)

😅 On self-hosting Durable Objects with workerd, "You beat us to it!" said Durable Objects creator Kenton Varda on Hacker News, later adding "celld is definitely ahead of us here. No doubt about that."

That Slow Tab Isn't the UI. It's the Query - TimescaleDB extends Postgres so queries stay fast at scale, straight from live data. Get $1000 credit to start.

Tiger Data (creators of TimescaleDB) sponsor

hucre 1.0: A Zero-Dependency Spreadsheet Engine - An MIT-licensed, tree-shakeable engine for reading and writing common spreadsheet formats, including support for things like embedded images, hyperlinks, password protection, and pivot tables.

Wind

vlt 1.0: An npm Alternative With CSS-Like Selectors - A drop-in npm alternative with a key draw being vlt query, which lets you use 60+ CSS-like selectors over your dependency graph (of which half are security related). vlt also offers hosted private package registries.

Darcy Clarke

TanStack Table v9: A Faster, More Modular Foundation - The headless table library gets a tree-shakeable architecture, state moves to TanStack Store for fine-grained reactivity, and there are big memory wins for large datasets.

Kevin Van Cott

• devalue 5.9 - The Svelte project's more powerful JSON.stringify supporting more JS language features.

• Svelte Select 6.0 - A select/autocomplete/typeahead Svelte component. Now requires Svelte 5.

• fuzzysort 4.0 - Fast, small fuzzy search library with ranking and custom scoring.

• GTKX 1.0 - Build native GTK4 desktop apps with React and TypeScript.

• Belgie 0.40 - Embeds a permissioned Deno runtime in Python.

📢 Elsewhere in the ecosystem

• The js1024 code golfing contest is over and we have three winners! Skydreams, a Super Monkey Ball-like experience, came in first place. You can read the readable and minified source if you want to see the techniques used.

• Docker has entered the agent sandbox game with Docker Sandboxes, a free way to run coding agents in their own microVMs with a Docker daemon inside.

• MCP goes stateless with the 2026-07-28 spec, so no more sticky sessions or open streams. Cloudflare covers what changed and what it takes to migrate.

• scriptc is a new, experimental TypeScript-to-native compiler from Vercel Labs. With --dynamic, unsupported or dynamic portions are run in a bundled QuickJS engine.

• 📊 The results of the State of CSS 2026 survey have been released.

I'm off on vacation at the end of this week, so see you again on August 25! Or in Node Weekly and React Status if you subscribe to those… ;-)

#​797 - August 4, 2026

Read on the Web

JavaScript Weekly

Next.js 16.3 Released - The newly expanded Next.js team (now including Dan Abramov and 𝕏 Pete Hunt!) has dropped the latest version of the popular React framework, complete with faster builds, optional TypeScript 7 type checking, faster SSR, Instant Navigations, AI improvements, and more.

The Next.js Team

Frontend Architecture: Monoliths to Microfrontends - Maxi Ferreira walks through modular monoliths, monorepos, and microfrontends so you can pick the right structure for your codebase and know the real cost before you commit.

Master.dev sponsor

Let's Make the Worst htmx Ever - After making the 'worst' React and Vue.js implementations, Serge tackles rebuilding the essence of htmx from scratch. A fun way to understand what htmx actually does under the hood.

Serge Zaitsev

The Secure Way to Release an npm Package in 2026 - A practical guide to publishing npm packages more safely, written by the author of numerous popular packages (e.g. postcss). As well as showing how to use staged publishing and trusted publishing, he explains why they help.

Andrey Sitnik

💡 GitHub is continuing to focus on npm security, and is starting to scan every npm package for malware at publish time. This will have some implications, including a delay between publishing and availability for installation.

IN BRIEF:

• 🚨 Developing incident: The popular keyv and cacheable packages were compromised today with a credential-stealing worm. The repercussions are ongoing with hundreds more packages compromised so far.

• Monthly updates from the Astro team and the Svelte team. The first preview releases of SvelteKit 3 are now available.

• ⚖️ The Deno vs Oracle JavaScript™ trademark case rattles on with Deno consenting to a fifth extension request as discovery continues.

• Popular JS library factory TanStack has rebranded and introduced new 'Markdown' and 'Highlight' libraries.

RELEASES:

• MobX 7.0 - The popular state manager slims down, removes deprecations, updates its React bindings, and now always uses Proxy-backed observable objects and arrays.

• Javy 9.1 - Toolchain for compiling JavaScript to WebAssembly for WASM runtimes.

• Node.js v26.6.0 (Current) and v24.19.0 (LTS)

• Vite 8.2, React Three Fiber 9.7, Lerna 10.0, Hono 4.13.0

📖 Articles and Videos

Your SPA is Leaking Memory: 'Soak Test' It - How to run a Playwright 'soak test' that loops a user flow within the same browser context, watches DOM node and listener counts, and fails CI when a memory leak creeps in.

Den Odell

Your JSON is Lying to You - A reminder that a JSON.parse/JSON.stringify round-trip is far from lossless, with big integers, undefined, Date, and more, altered or lost along the way. Gabor covers the nastier gotchas and practical ways to make the conversion boundaries explicit.

Gabor Koos

Don't Just Code-Grow as a Technologist - Explore new technology, sharpen your existing skills and build new ones when you work in tech at Fidelity.

Fidelity Careers sponsor

cdnjs at 9 Billion Requests a Day: A Migration Story - cdnjs is a popular, free CDN for loading JavaScript libraries without bundling or self-hosting (which LLMs really seem to like). Cloudflare explains how it now runs entirely on Workers and R2.

Simona Badoiu (Cloudflare)

Adding Go's defer to the TypeScript Compiler - In Go, defer delays the execution of a function call until the surrounding function finishes. Can you just fork TypeScript and add language features? Yes! Should you? Probably not, as using is already a good fit for the use case.

Andrew Healey

📄 Learning Remix 3 - By porting a Solid 2.0 demo to Remix 3's server-first model. Mark Malstrom

📄 Why npm Dependency Trees Are So Big Andrew Nesbitt

🛠 Code & Tools

TanStack Charts: A New Chart Grammar Option - In the past few weeks, TanStack has been rapidly iterating on a new, framework-neutral way to declaratively specify a large number of chart-related visualizations in JavaScript. Output renders to SVG or canvas and can be styled as you wish. Here's a comparison against other established options.

TanStack

An Open Source PR Reviewer Just Ranked #2 of 42 on Code-Review-Bench - PR-AF outranks the commercial tools. Verified findings only, ~10x cheaper, self-hosted. Drops into GitHub Actions.

Agentfield.ai sponsor

MicroDiff 1.6: Fast Object and Array Comparison Library - Given two objects or arrays, it returns the differences (think diff but for JS objects). This week's release adds support for Temporal types.

Jacob Jackson

💡 Jacob has a post from 2022 covering how microdiff is so fast.

Virtua: Virtual List and Grid Component for Multiple Frameworks - A fast and small virtual list/grid component for React, Vue, Solid, Svelte, and Angular. Here's a demo and a comparison table against other solutions.

inokawa

📊 Perspective 5: Interactive Analytics and Data Vis Component - Originally built by JP Morgan, a WASM-powered data visualization component suited to large and/or real-time streaming datasets. 5.0/5.1 just dropped with numerous fixes, wasm64 builds, and window columns.

OpenJS Foundation

• Neutralinojs 6.9 - The lightweight Electron alternative has a new C++ network API for making HTTP requests free of the webview's CORS restrictions.

• DukPy 0.6 - Simple JavaScript interpreter for Python. Now uses the QuickJS-NG engine to support more modern JavaScript and Promises.

• isomorphic-git 1.40.0 - A pure JS implementation of Git for Node & browsers.

• better-result 3.0 - Lightweight Result type for TypeScript with generator-based composition.

• ip-address 10.4 - Parse, validate and manipulate IP (v4 and v6) addresses.

📢 Elsewhere in the ecosystem

• Did you know JavaScript supports a third type of comment (beyond // and /* */)? ▶️ Mat Marquis shows off hashbang comments in a short YouTube video. And yes, they're in the language spec!

• 🤖 GitHub's Sean Goedecke says LLMs reward expertise, with the most important prompting skill being expertise in the domain you're prompting for.

• Microsoft is previewing a way to call native Windows APIs from Node (and therefore Electron) without native addons, via a new dynamic Windows Runtime API (WinRT) projection.

• Cloudflare Workers has added support for inbound TCP connections and gRPC (in private beta).

• Stacked pull requests are now in public preview on GitHub.

#​796 - July 28, 2026

Read on the Web

JavaScript Weekly

Rust Is Eating JavaScript (Still, in 2026) - Our most-read link of 2021 gets an update for 2026. Lee Robinson (then Vercel, now Cursor) predicted Rust would be used to reimplement more and more JavaScript ecosystem tooling, and Rspack, Biome, Turbopack, and Bun's recent rewrite keep proving him right.

Lee Robinson

Frontend Architecture: Monoliths to Microfrontends - Maxi Ferreira walks through modular monoliths, monorepos, and microfrontends so you can pick the right structure for your codebase and know the real cost before you commit.

Master.dev sponsor

Octane: React's Programming Model, But Compiled - From the creator of Inferno comes a successor: a compiled React-like framework (differences explained here) that generates reactivity ahead of time with no VDOM. Supports TSX/JSX and TSRX, with integrations for TanStack Query and Router, plus other common React libraries.

Dominic Gannaway

IN BRIEF:

• 😄 htmx 4.0 is, curiously, pitching itself as "the first JavaScript library to release exclusively on the Game Boy" with a commemorative cartridge.

• At last week's TC39 meeting, Await Dictionary (Promise.allKeyed) progressed to Stage 3.

• Ryan Dahl says that deno compile will soon support using QuickJS instead of V8 for making radically smaller binaries from JS/TS projects.

• Node.js has a new API docs site in preview (now includes search!)

• Oxlint's type-aware linting is now stable.

RELEASES:

• pnpm has had a flurry of releases introducing native workspace release management, a doctor command to diagnose installation issues, and more.

• React 19.2.8, 19.1.9 and 19.0.8 to fix a potential DoS vulnerability in server function endpoints.

• Ember 7.1 - Adds a wide variety of new helpers and operators, and docs modernization.

• Nuxt 4.5.1 and 3.21.10 - Security patch releases after last week's big Nuxt 4.5 release.

• ESLint 10.8, Deno 2.9.4, Prisma 7.9, React Router 8.3, Vue 3.6 RC2

📖 Articles and Videos

▶ The Creator of TypeScript Shows Off TypeScript 7 - Anders Hejlsberg demos the 10x speedup gained by the new Go-based TypeScript compiler on VS Code's 1.3M line codebase. He also covers the new LSP language server and why compiler API users (Vue, Astro, Svelte) must stay on TypeScript 6.

Anders Hejlsberg (Microsoft)

Domenic Denicola's Agentic Coding Setup - It's fascinating when a prolific developer (Domenic was a key figure in the adoption of promises in JavaScript, creating jsdom, and much more) shares their workflow. This is no exception, covering areas like disposable VMs, Tailscale, and worktrees.

Domenic Denicola

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

How Medium Built Its New 'Table of Contents' Feature - How the content site built a dynamic table of contents widget for all its articles, inspired by a third-party Chrome extension that did the same thing.

Scott Batson (Medium)

📄 Introducing Deferred Module Evaluation with import defer - Currently at stage 3 in the TC39 process. Nitay Neeman

📄 Measuring Component Performance with the Container Timing API - Now in a Chrome origin trial. Harry Roberts

📄 No, We Can't Harden Node.js Against Prototype Pollution Matteo Collina

📄 Cloudflare Workers and Hyperdrive with SvelteKit Adam Rackis

🛠 Code & Tools

🌐 MapLibre GL JS 6.0: Interactive Vector Maps for the Web - A WebGL-powered library for rendering interactive vector tile maps, forked from Mapbox GL JS after its 2020 relicensing. Version 6 goes ESM-only, requires WebGL 2, and lands broad performance gains. Release notes and a v5 to v6 migration guide.

MapLibre

Ship Translations Without Redeploying. Made by the i18next Team - The cloud TMS from the i18next team. saveMissing, in-context editor, AI translation, CDN. Free tier, Swiss-made.

Locize sponsor

Bruno 4.0: An Open-Source HTTP API Client App - An open source, JavaScript-powered lightweight alternative to something like Postman for testing and making requests against HTTP APIs.

Anoop M D, Anusree P S and Contributors

tslog 5: Zero-Dependency Logger for Node, Deno, Bun and Browsers - A ground-up rewrite, now ESM-only, and also covers workers and React Native. Pretty output by default, JSON optionally, plus middleware, file/HTTP/worker transports, secret masking, and error stacks that resolve through source maps to your original .ts lines. GitHub repo.

Eugene Terehov

eslint-package-json: Powerful ESLint Rules for package.json - An ESLint plugin that catches package.json mistakes like invalid names, bad version ranges, broken exports, redundant files entries, and more, and fixes many of them automatically.

Sindre Sorhus

Shadscan: Deterministic UI Audits for shadcn Apps - A tool that statically analyzes your shadcn components using almost 60 deterministic checks (no AI or API keys needed) around fundamental accessibility, state, and composition best practices.

OrcDev

• Slick 2.0 - Ken Wheeler's classic jQuery carousel control (demos). Now compatible with jQuery 4.0!

• isomorphic-git 1.40 - Pure JS implementation of Git for Node and browsers.

• Satori 0.29 - Library to convert HTML and CSS with JSX syntax into SVG.

• dompdf.js 2.0 - Converts HTML to multi-page PDFs in the browser.

• Verdaccio 6.9 - Self-hostable Node.js private proxy registry.

📢 Elsewhere in the ecosystem

• js1024 is an annual JavaScript code-golfing competition where people try to squeeze as much out of 1024 bytes as possible. This year's run just closed and you can try all the entries (and see their code) here - the winners will be announced next week.

• 🏆 The OpenJS Foundation has a ranking of the top contributors to its projects (which include Node, Express, and Electron) in the past year.

• 🤖 In How I Stopped Running Out of Tokens, a dev whose company uses Claude Enterprise shares tools you can use (e.g. rtk) to get more out of your limits.

• LLMs are continuing to hallucinate package names, giving potential 'slopsquatters' opportunities for malicious deeds.