fidzu : javascript

#​790 - June 16, 2026

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JavaScript Weekly

Flow for TypeScript Users in 2026 - Flow is Meta's mature typed dialect of JavaScript, and over the years its syntax has converged closely with TypeScript's. This post walks through where the two now differ: Flow's stricter defaults reject several crash-prone patterns TypeScript's strict mode accepts, and it adds features of its own, like exhaustive match expressions.

George Zahariev (Meta)

Free Claude Code Course from Anthropic + Master.Dev - Coding is changing fast, and the engineers who thrive will be the ones who direct AI instead of guessing at it. Lydia Hallie from Anthropic teaches exactly that in our Claude Code course, now free for everyone.

Master.dev sponsor

npm v12 to Stop Running Install Scripts by Default - The forthcoming npm v12 will no longer execute preinstall/install/postinstall scripts, unless you explicitly allow them. You can get ready now by using npm 11.16.0 which prints warnings about anything v12 would block.

GitHub

🤖 Code is Cheap(er) - The creator of htmx says that while code is increasingly easy to produce, understanding is still expensive, and "complexity remains our apex predator."

Carson Gross

IN BRIEF:

• The pnpm team has created a new GitHub Action to set up both pnpm and a JS runtime (Node, Deno, or Bun).

• 🐈 Compilecat (repo) is a new, experimental JavaScript performance compiler that does Closure-style optimizations.

• Several major projects are taking shape in beta/pre-release stages right now, including SvelteKit 3.0, Vue 3.6, Vite 8.1, and Astro 7.0.

RELEASES:

• Playwright 1.61 - You can now register and test passkeys, as well as read/write to localStorage and sessionStorage via a new WebStorage API.

• ESLint v10.5.0 - Five core rules now highlight smaller ranges of code to avoid shadowing other problems in editors.

• 🤖 TanStack AI Beta - Framework and provider-agnostic AI toolkit.

📖 Articles and Videos

How TanStack Cut TypeScript Type-Checking Work by Up to 86% - TanStack Table v9 (now in beta) made its features modular, but the generic types behind that flexibility introduced noticeable editor lag in alpha. This deep-dive shows how the team used tsc diagnostics to cut type-checking work by 62-86%, with lessons for anyone authoring type-heavy libraries.

Kevin Van Cott (TanStack)

🛠️ React Libraries and Tools for 2026 - Every year, Robin updates this post covering his opinionated list of essential React ecosystem libraries.

Robin Wieruch

Your AI Writes Tests That Pass but Prove Nothing. Fix It - Wallaby CLI makes test generation 10x smarter with live coverage and runtime data, using 3x fewer tokens. One skill to install.

Wallaby Team sponsor

Changing the Kindle's Homepage by Editing Hermes Bytecode - The Kindle's UI now runs on a Hermes-powered JavaScript stack. Here's how you can edit the bytecode Hermes produces to change the Kindle UI's behavior.

Nicholas Tarta

📈 Making numpy-ts as Fast as Native - How a TypeScript NumPy port went from 15x slower to matching native, by changing not whether to use WASM, but who owns the bytes.

Nico Dupont

📄 How Building an HTML-First Site Doubled Our Users Overnight - Out with the React, and in with the Astro. Alistair Davidson

📄 Building a Real Blog Easily in Astro - By real, Zell means something beyond demo-level, with excerpts, post update dates, etc. Zell Liew

📄 Streaming HTML with textStream() in Chrome Canary Ollie Williams

🛠 Code & Tools

eslint-plugin-unicorn 67.0: More Than 200 Powerful ESLint Rules - Sindre's set of curated rules has grown a lot, with almost 100 added or updated in the past few weeks alone. Like enforcing better comments, limiting the depth of nested calls, preferring Temporal over Date, and preferring HTTPS over HTTP in URLs. These rules will seriously challenge (and improve!) your code.

Sindre Sorhus et al.

zod-compiler: Compile Zod Schemas into Zero-Overhead Validators - A build-time compiler that plugs into Vite, webpack, et al. and rewrites existing schemas into optimized, tree-shakeable validators. Claims 2-75x faster validation with no source changes and the full Zod API preserved.

Gajus Kuizinas

That Slow Analytics Endpoint? It's a Database Problem - Pipelines, sync lag, stale data. That's the cost of a split stack. TimescaleDB extends Postgres so your app stays fast.

Tiger Data (creators of TimescaleDB) sponsor

📊 billboard.js 4.0: A JavaScript Chart Library Based on D3 - At almost nine years old, billboard.js now has a new, opt-in canvas-based rendering mode (SVG remains the default), smaller bundles, and better performance on large datasets. There are hundreds of demos ranging from donut charts and funnel charts to overlapping bar charts and radar charts.

Jae Sung Park (NAVER)

PolyCSS: CSS 3D Engine for the DOM - Renders textured 3D polygon meshes entirely in the DOM using CSS matrix3d() transforms - no WebGL or <canvas> required. Works with vanilla JS, React, and Vue. There's a gallery to explore and a live builder if you want to play around.

LayoutitStudio

• Tabulator 6.5 (above) - Create interactive tables from any HTML table, JS array or JSON data.

• 🕒 <relative-time> 5.2.0 - Web Component for formatting automatically-updating timestamps as localized strings or relative times.

• Fable 5.2 - No, not the LLM you can't use, but an F# to JS/TS (and now Erlang too) compiler you can use. More info.

• React Native 0.86 - Edge-to-edge support on Android 15+ and improvements to its DevTools.

• Biome 2.5 - The fast code formatting and linting toolchain has now passed 500 lint rules.

• get-value 4.1 - Use paths like a.b.c to get a nested value from an object.

• axios v1.18.0 - Promise-based HTTP client for the browser and Node.

• 📊 visx 4.0 - Airbnb's visualization primitives for React.

📢 Elsewhere in the ecosystem

• 🌐 The WebKit team shows off MapKit JS 6 (above), a way to integrate Apple Maps into your site like in this example. You need a token from an Apple Developer account though.

• 😱 A developer was sent a malicious JavaScript 'coding test' by a fake recruiter on LinkedIn in an attempt to backdoor his machine. I've heard about this vector a few times this year, so be careful.

• WASI 0.3 (WebAssembly System Interface) has launched, bringing native async support to WebAssembly Components.

• performative-ui is a fun set of modern clichéd "AI startup" UI components for React, like ASCII hero art and node graph backgrounds.

• A dev had an old USB scanner with no modern drivers, but got it working via a browser-based WASM-powered emulator bridged to the physical scanner through WebUSB. He previously did something similar with an old printer.

#​789 - June 9, 2026

Read on the Web

JavaScript Weekly

VoidZero is Joining Cloudflare - One of the year's big moves in JS tooling, as told by Evan himself. The company he founded to build Vite, Vitest, Rolldown, Oxc, etc. is joining Cloudflare. He's candid about why (monetization is hard). Good news: all projects stay MIT-licensed, and Evan and co remain in charge.

Evan You

💰 In the Vite team's post, they reveal Cloudflare is starting a $1 million fund to support Vite ecosystem maintainers and contributors.

Come for Great PostgreSQL Talks - Virtual and Free - Attend talks about PostgreSQL-backed app development at POSETTE: An Event for Postgres 2026 (16-18 June). Join live and chat directly with PostgreSQL speakers, other developers and users. There is also swag waiting for you. Register for updates.

Microsoft | AMD sponsor

Announcing Angular v22 - Google's batteries-included framework graduates three big features to stable/production-ready: Signal Forms, Angular Aria, and asynchronous reactivity. The router also adds experimental support for the native browser Navigation API.

The Angular Team

IN BRIEF:

• Safari 27 (beta), announced at WWDC, includes a standards-compliant ESM loader rewrite improving top-level await support, and adds support for JSPI (JavaScript Promise Integration) in WebAssembly.

• Electron 43 is in beta with big perf boosts, thanks to an embedded Node.js snapshot, bundles cached as V8 bytecode, and link-time optimization on the main binary.

• The Rust port of React Compiler is ready to test (Meta is already seeing "great results") - it's set to be merged imminently.

RELEASES:

• TanStack Table v9 Beta - A powerful headless engine for creating data grids with support for React, Preact, Solid, Vue, Angular, Svelte, and Lit.

• Node-RED 5.0 - 'Low-code' flow programming environment, built on Node.js.

• Rolldown 1.1, pnpm 11.5, RunJS 4, Emscripten 6.0

📖 Articles and Videos

Modern Engineering Values - "I cannot believe that I used to write code by hand!" The creator of Jest and Fate says that as agents write more software, the engineering values that matter shift, with ownership, taste, and strict-but-fast feedback loops at the fore.

Christoph Nakazawa

'I Wish Deno Would Keep Doing What It Does Best' - A Deno fan argues that chasing Node.js/npm compatibility is costing the runtime its edge as a zero-config, web-standards, all-in-one-binary experience.

Hong Minhee

How Is Your App Performing in Production? - Ship a release this morning. By tonight you can know if the app got faster, slower, or worse for any specific cohort of users.

Expo sponsor

What Bun Can Tell Us About AI and Open Source - An analyst looks at Bun, whose code is increasingly AI-produced rather than human-written, as a bellwether for whether AI-authored core infrastructure is sustainable.

Stephen O'Grady (RedMonk)

📺 All 17 TanStack Projects in One App - TanStack is now a huge suite of libraries, and if anyone can pull them all into one app, Jack can! Jack Herrington

📄 Everything You Need to Know About Source Maps Neciu Dan

📄 How TypeScript Infers Type Variables Nicolas Laurent

🛠 Code & Tools

Geometric.js: A Library for Doing Geometry - Created by someone who works on graphics for the NYT, this elegant library lets you work with polygons, bounding boxes, reflection, interpolation, rotation, and the like (examples). Does one polygon intersect with another? There's a function for that.

Harry Stevens (The New York Times)

Ship Real-Time Features Without a Second Database - TimescaleDB extends Postgres for live analytics on event data. No pipeline, no extra infrastructure. $1000 credit.

Tiger Data (creators of TimescaleDB) sponsor

Micromodal.js: A Tiny Library for Accessible Modal Dialogs - No-dependency library for WAI-ARIA guideline-compliant modal dialogs. Offers extra polish versus <dialog>, with hooks, scroll-locking, in/out transitions, and click backdrop to dismiss.

Ghosh and Singh

📝 PDFSlick 4.0: View and Interact with PDFs in JS Apps - A PDF viewer for React, Solid, Svelte & vanilla JS apps that goes from simple PDF viewing up to working with multiple, large documents with annotations. Demo.

Vancho Stojkov

babel-plugin-zod-hoist: Hoist Zod Schema Definitions to the Top of the File - From the creator of Slonik comes a way to make Zod validation significantly faster.

Gajus Kuizinas

• eslint-plugin-functional 10.0 - Linter rules to disallow mutation and encourage functional programming.

• ts-loader 9.6 - The TypeScript loader for webpack adds webpack 4 support back again.

• 🧊 Draco.js - A pure JS Draco mesh loader for three.js by mrdoob himself. (Demo.)

• Taiga UI 5.10 - Popular suite of 50+ components for Angular.

📢 Elsewhere in the ecosystem

• Oxide Computer Company's Mitos ASCII Tool (above) converts images into ASCII text illustrations and animations, by way of a built-in livecoding environment (built upon the fantastic play.core).

• 🔁 replacements.fyi, from the e18e team, is a handy way to find replacements for npm packages of your choice, whether that's a simpler package, a code snippet that does the same thing, or a native API.

• ⚡ Add Obs.js to a page and it adds classes to <html> to customize the UX based on how much performance is available (e.g. bandwidth, CPU, latency). Harry Roberts explains further.

• 🕹️ Raymond Camden set out to see if Chrome's built-in AI could play Zork 1, the classic text adventure game.

#​788 - June 2, 2026

Read on the Web

JavaScript Weekly

Hocuspocus 4: Add Real-Time Collaboration to Any App - A plug-and-play real-time collaboration backend based on Yjs so you can quickly and safely wire up multi-user collaborative experiences into a JavaScript app. It runs on Node, Bun, Deno, or Cloudflare Workers. GitHub repo.

Tiptap

Still Writing Tests Manually? Meticulous AI Is Here - Notion, Dropbox, Wiz and LaunchDarkly now use a testing paradigm they can't work without. Built by former Palantir engineers, Meticulous automatically creates an evolving suite of E2E UI tests, delivering exhaustive coverage with no developer effort.

Meticulous sponsor

How to Evaluate an npm Package: 2026 Edition - A practical checklist for vetting packages beyond star counts, covering provenance attestation, install scripts, CI quality, and maintainer responsiveness. Learn to spot the red flags before you npm install.

Gabor Koos

IN BRIEF:

• 🕒 The popular date-fns date utility library is preparing for a Temporal shaped future and becoming a "Temporal-first library". For now, a much leaner v4.4 is available, and v5.0 just entered alpha.

• 🔒 In the latest surfacing of Shai-Hulud, dozens of Red Hat npm packages have been backdoored.

• npm 11.16.0 has shipped with initial (advisory warning only) support for an opt-in install-script policy using allowScripts. More details here.

• The Svelte team presents its latest monthly update.

RELEASES:

• Ember 7.0 - A major release for the long-standing framework to remove deprecated features. This post rounds up everything new since 6.0.

• Node.js 26.3.0 (Current) - npm is upgraded to 11.16.0, macOS x64 gets demoted to a tier 2 platform, and QUIC gets a big batch of improvements.

• Astro 6.4 - The web framework adds a pluggable Markdown pipeline, a Rust-based Markdown processor, and helpers for advanced routing on Cloudflare.

• pnpm 11.5.0/11.5.1, ESLint 10.4.1, Angular 22 RC3

📖 Articles and Videos

🤖 Using AI to Write Better Code More Slowly - A prolific JavaScript developer says LLMs aren't just for pumping out bad code quickly, they can indeed help you write higher quality code more slowly.

Nolan Lawson

TypeScript Tips Everyone Should Know - A concise set of tips for safer and cleaner code, as well as a reminder that while TypeScript can improve correctness, it doesn't guarantee good architecture or eliminate runtime bugs.

Matt Smith

Your Partition Scheme Made Sense. Then the Data Got Big - TimescaleDB extends Postgres so analytics queries stay fast at scale. No pipeline, no second database. $1000 credit.

Tiger Data (creators of TimescaleDB) sponsor

Intentionally Blocking Rendering with JavaScript - "Sometimes an inline render-blocking script is a small price to pay for avoiding aggressive layout shifts."

Jay Freestone

Why Does tsgo Use So Much Memory? - A look into the Go-powered TypeScript 7 compiler and why it can chew through gigabytes on a large project.

Zack Radisic

📄 CSS vs. JavaScript for Web Animations - Underlying performance differences and guidance on when to pick which approach. Josh W. Comeau

📄 Your Recursion is Lying to You - ES2015 specified tail call optimization, but most engines in 2026 don't support it. Gabor Koos

📄 How We Cut Build Times by Two-Thirds by Deleting Our CMS - The story of Sentry's Gatsby to Astro migration. Eli Lennox (Sentry)

📄 Creating a VS Code Agent Hook to Respond to File Changes Nicholas C. Zakas

🛠 Code & Tools

📊 Plotly 3.6: The Declarative Graphing Library - A long-standing library, also widely used in the Python and R ecosystems, that offers over 50 visualization types, from basic charts and graphs to maps, plots, and heatmaps.

Plotly, Inc.

Expo UI Is Stable. Real SwiftUI and Compose from JS - One import. SwiftUI on iOS, Jetpack Compose on Android. Plus native drop-in replacements for 7 community packages.

Expo sponsor

Component Party: A Rosetta Stone of UI Libraries - A side-by-side code snippet comparison of frameworks including React, Vue, Svelte, Angular, Ember, and more obscure options. Recent updates have extended Angular and Svelte coverage, plus added Ripple and Ember Polaris to the mix.

Mathieu Schimmerling

🎉 tsParticles 4: A Particle Engine for Web Effects - If you want a confetti cannon, fireworks, ribbons, fireflies, snow, or similar effects on your pages, this is for you. Supports all major frameworks and vanilla JS. You can see some live demos here.

Matteo Bruni

• 📝 officeParser 7.1 - Parse 'office' files (e.g. docx, pptx, xlsx, odt) into an AST. The in-browser demo shows off what's returned.

• 🔎 Fuse.js 7.4 - JavaScript fuzzy-search library. v7.4 adds support for parallel search powered by Web Workers. (Homepage)

• ESLint You Might Not Need An Effect 1.0 - ESLint/Oxlint plugin to catch when you might not need an Effect in React.

• PGlite 0.5 - Run a Postgres database locally in WASM with reactivity and live sync. v0.5 upgrades to Postgres 18.3.

• TinyBase 8.4 - A reactive data store and sync engine for local-first apps. Now with full SolidJS support.

• Sugar High 1.2 - 1KB syntax highlighter for JavaScript and JSX.

• Mantine 9.3 - Popular, extensive React component suite.

📢 Elsewhere in the ecosystem

• Programming language legend ▶️ Anders Hejlsberg was on The Pragmatic Engineer talking about his background, work on TypeScript, JavaScript's strengths and weaknesses, and how he uses AI.

• Kyle Simpson (of YDKJS fame) got in touch minutes before we hit send to let us know about @gql-x/Composer, a new library he's working on that's a JavaScript DSL for dynamically composing GraphQL query strings.

• A new way for sites to sneakily track users with JavaScript has been demonstrated. It involves analyzing SSD usage by using the Origin Private File System feature.

• 🤖 The results of the State of Web Dev AI 2026 survey are ready to enjoy with stats on AI use from over 7,000 developers.