Jeff Posnick

@jeff.posnick.org

Working on developer experience & tooling at Bloomberg. https://jeffy.info

I want to see more @puzzmo.com accounts when I'm on Bluesky! Help me juke my stats, if you've hooked it up and got the label, but don't have a paid account; DM me your profile link over the next week and I'll gift you a year's sub (The link is in the dropdown when you click on your nav avatar)

Bloomberg uses a lot of C++ & contributes to the standard as well as various industry conferences and libraries. I’m looking for an experienced engineer to join a distributed systems team in New York working on our core Deployment Infrastructure for the Bloomberg Terminal 🗽 🧵

Five engineers in a glass meeting room with a whiteboard wall

This is a place where every day you wake up, you could experience everything from a basketball player crashing into our old mayor to a person who's celebrating a new business that's opening

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PWA Plugin v2 will be a necessary "clean break": Vite 8 + Rolldown required. ⚡️ 🚀 Native "Dual Service Worker" support: we serve native ESM to modern browsers and automatically fallback to Classic for the rest. The best of both worlds with zero config! ✅🚀 @vite.dev #PWA

I just published a deep-dive into the 250-hour build behind syntaqlite, a SQLite formatter and LSP I built using AI agents. AI agents were the only reason built this after 8 years of wanting but there's a psychological toll to AI-assisted engineering. The post-mortem: lalitm.com/post/buildin...

Eight years of wanting, three months of building with AI

For eight years, I’ve wanted a high-quality set of devtools for working with SQLite. Given how important SQLite is to the industry1, I’ve long been puzzled that no one has invested in building a reall...

lalitm.com

What if you could collect Wikipedia articles and make them battle? Wikigacha, created by Japanese developer Haruki Sugiyama, turns every Wikipedia article into a collectible trading card.

ECMAScript excitement 😉 This week in NY @tc39.es advanced these proposals 🎉 4⃣ Intl Era/Month Code 4⃣ Temporal 3⃣ Import Text 2⃣.7⃣ Error Stack Accessor 2⃣.7⃣ Iterator Includes 2⃣ Intl Unit Protocol 2⃣ Thenable Curtailment 1⃣ Error Code Property 🗑️ Dynamic Import Host Adjustment

Delegates of TC39 in Google's Chelsea Market office

Source maps are a vital part of modern web development, but the lack of a standard made it impossible for us to add new features or improve the debugging experience. This is the story of how we standardized source maps and how we continue to ship features through standards 📜 🧵

A JSON file representing a source map. The code contains:

{
  "version": 3, // Always the integer 3
  "file": "out.js", // Optional: name of the generated file
  "sourceRoot": "", // Optional: prefix prepended to each entry in "sources"
  "sources": ["foo.js", "bar.js"], // Required: list of original source URLs/paths (or null)
  "sourcesContent": [null, null], // Optional: inlined source text, aligned with "sources"
  "names": ["src", "maps"], // Optional: symbol names referenced by "mappings"
  "mappings": "A,AAAB;;ABCDE", // Required: encoded mapping data (base64-VLQ deltas)
  "ignoreList": [0] // Optional: indexes into "sources" considered "third-party"
}

Some time ago, @jonkuperman.com & @tchetwin.bsky.social had a dream for the JS engineers at Bloomberg to be more public about the cool JS work we have going on. That dream has come true - now we have a blog platform 🎉 (You'll see more articles over the next few days) bloomberg.github.io/js-blog/

Bloomberg JS Blog

The official Bloomberg JavaScript blog - insights, tutorials, and best practices from Bloomberg's JavaScript engineering team.

bloomberg.github.io

This is a welcome change. Puzzmo is my most-used Progressive Web App! www.puzzmo.com/user/fy/jpo34

@jpo34 on Puzzmo

Re-imagined mainstays like the daily Crossword Puzzle, modern classics like Really Bad Chess and SpellTower, and even a few brand new puzzles.

puzzmo.com

Orta Therox@orta.io · 6mo ago

- "Follows not Friends" - we've changed the core relationship dynamic on @puzzmo.com to make relations easier to setup - Puzzmo staff are friends by default ala Myspace Tom - Fancy opengraph images for your public profile URL - Friends / Groups / Community leaderboards are all on by default

I refuse to shut up about this: NYC started charging $9 to bring a car into our most transit-rich zone, the haters & trolls predicted doom, but traffic evaporated instantly and here’s Times Square tonite (even after the holiday tourists have left). For a better future, build transit & price driving!

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ECMAScript excitement 😉 TC39 has a *packed* agenda for next week & will consider advancing: 4️⃣ Intl.Locale info 4️⃣ Iterator Sequencing 4️⃣ JSON.parse source 3️⃣ Intl Era Month Code 3️⃣ Joint Iteration 2️⃣.7️⃣ Error.prototype.stack 2️⃣.7️⃣ export defer 2️⃣ Amount 2️⃣ await dictionary 2️⃣ Declarations in Conditionals 🧵

19h 50m of scheduled discussions annotated with a shocked face

Agenda for the 111th meeting of Ecma TC39
Host: Bloomberg
Dates and times:
10:00 to 17:00 JST (Asia/Tokyo) on Tuesday 18 November 2025
10:00 to 17:00 JST (Asia/Tokyo) on Wednesday 19 November 2025
10:00 to 16:00 JST (Asia/Tokyo) on Thursday 20 November 2025
Location: Tokyo, Japan