Independent software developer, formerly @sidewalklabs and Google. Author of Effective TypeScript, now in its 2nd edition (May 2024): amzn.to/3UjPrsK
Joined February 2009
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9 May 2024
It's here! 🎉 The 2nd edition of Effective TypeScript is now available in all formats. The bird on the cover is the same, but the content is throughly revised and expanded to reflect how TS is used in 2024. Get your copy today! @OReillyMedia amzn.to/3UjPrsK
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23 May 2025
Great article from @ollie about my long-running quest to find the highest-scoring Boggle board. I love the visuals! ft.com/content/0ab64ced-1ed1…
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writing typescript for the first time in 6 years, and i think im enjoying it? new additions like type predicates inference make for a much nicer devex
found a very cool article too documenting the development process of this feature from @danvdk
effectivetypescript.com/2024…
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8 Oct 2024
Just published a big update to my "X-Ray Glasses for any types" VS Code extension: marketplace.visualstudio.com…
It uses the built-in TypeScript server now, which makes it faster and more likely to work with your project. Give it a try! It found some anys in vscode and tsc itself!
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Dan Vanderkam 🦋 retweeted
Just started reading the 2nd edition of this book 🎉
I can’t recommend it enough! The first version made me an entire new dev.
9 May 2024
It's here! 🎉 The 2nd edition of Effective TypeScript is now available in all formats. The bird on the cover is the same, but the content is throughly revised and expanded to reflect how TS is used in 2024. Get your copy today! @OReillyMedia amzn.to/3UjPrsK
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29 Sep 2024
For a weekend project, I wrote a VS Code extension: X-Ray Vision for any types. The scary thing about "any" is that it can appear in surprising place and silently spread. No more! This was frustrating, rewarding, and hopefully useful. Give it a try! marketplace.visualstudio.com…
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30 Aug 2024
This is the single passage of Effective TypeScript that I've received the most feedback on. Do you have an intuition for why these relationships hold? The latest blog post walks through how they work, what they mean, and why they're interesting effectivetypescript.com/2024…
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17 Jul 2024
I learned Zig for last year's Advent of Code. It's a nice language with some great ideas, and TypeScript could learn a few things from it. Read on! effectivetypescript.com/2024…
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2 Jul 2024
My notes on the changes in TypeScript 5.5, a blockbuster release effectivetypescript.com/2024…
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20 Jun 2024
I'm very excited that TS 5.5 has officially landed with Inferred Type Predicates, the feature I built at @recursecenter earlier this year. Read all about the journey at effectivetypescript.com/2024…. Special thanks to @AndaristRake for fixing all my bugs :)
20 Jun 2024
TypeScript 5.5 is now available! 🎉✨
Now with
✅ Inferred Type Predicates
✅ RegEx syntax checks
✅ The JSDoc @import Tag
✅ ${configDir} for easier tsconfig inheritance
✅ --isolatedDeclarations
✅ Lots of new optimizations
And more! Try it today!
devblogs.microsoft.com/types…
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20 Jun 2024
or if you prefer videos, check out the great discussion that @JoshuaKGoldberg and I had with Dimitri from @MiTypeScript youtu.be/LTuzl2r2HjA
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13 Jun 2024
Effective TypeScript Item 36: Use a Distinct Type for Special Values.
This is a sample from the newly-released second edition. It discusses a common mistake in TypeScript code: using "", 0, or -1 to represent special cases like missing data. effectivetypescript.com/2024…
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Dan Vanderkam 🦋 retweeted
13 Jun 2024
TypeScript 5.5's going to be a BANGER, and the headliner feature for a lot of us that I'm SO EXCITED about is because @danvdk wanted to be awesome.
Congrats and thank you Dan for inferred type predicates!
It was an honor just to cheer it on. 😄
12 Jun 2024
If you want to learn the backstory of TypeScript 5.5's inferred type predicates, this is the video! I'm really happy with how it turned out. Kudos to Dimitri and @JoshuaKGoldberg for putting it together.
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12 Jun 2024
If you want to learn the backstory of TypeScript 5.5's inferred type predicates, this is the video! I'm really happy with how it turned out. Kudos to Dimitri and @JoshuaKGoldberg for putting it together.
12 Jun 2024
🤩 a super long-requested @typescript feature is coming in a few days to v5.5: @danvdk's work on inferred type predicates! So, naturally, we did a deep dive on it with Dan, the PR author himself!
video link below👇
ALT INCREDIBLE new feature in TypeScript 5.5. Interview with the PR author! RELEASE REPORT
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Dan Vanderkam 🦋 retweeted
29 May 2024
This is the thing! We're launching!
I'M CO-ORGANIZING A CONFERENCE THIS YEAR!!!!
SO MUCH WORK has gone into it and I'm SO HYPED TO GET IT PUBLIC!!
🤩🥳🤩🥳🤩🥳
29 May 2024
👋 Hello world! We’re so excited to finally be ready to meet you.
Welcome to SquiggleConf: a Boston conference for excellent web dev tooling. 💙
🐟 October 3rd-4th in the Simons Theater at the New England Aquarium.
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Dan Vanderkam 🦋 retweeted
26 Apr 2024
I'm always excited by a TypeScript release. This one is epic, and what's all the notable is how much community involvement there was in it. I loved seeing the shout outs to @TitianCernicova, @danvdk and others in the release post. Recognition is so important and so appreciated ❤️
25 Apr 2024
Announcing TypeScript 5.5 Beta! 📣
Now with type predicate inference, more type narrowing, an @import tag for JSDoc, the --isolatedDeclarations flag, performance & reliability improvements, and much more!
devblogs.microsoft.com/types…
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26 Apr 2024
Very excited to see inferred type predicates headline TS 5.5! I hope everyone enjoys the bird-themed release notes 🦜
25 Apr 2024
Announcing TypeScript 5.5 Beta! 📣
Now with type predicate inference, more type narrowing, an @import tag for JSDoc, the --isolatedDeclarations flag, performance & reliability improvements, and much more!
devblogs.microsoft.com/types…
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25 Apr 2024
This has been on my list of most-desired TS features for years. I’m genuinely curious to see what breaks under —strictReadonly. In 2016 this felt too strict, but in 2024 it’s surprising we don’t have this.
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16 Apr 2024
One of my goals this year was to become a TypeScript contributor. Over the past three months, I did just that! This post tells the story of how Type Predicate Inference came about and what I learned along the way. effectivetypescript.com/2024…
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5 Apr 2024
Excited to see that the new Flow Node Charts have at least one high-profile user. And may have even indirectly led to some TypeScript speedups! Visualizing something has a way of nudging you to make it better. @DavidSherret github.com/microsoft/TypeScr…
28 Feb 2024
For my PR to infer type predicates, I needed to understand TypeScript's control flow graph. So I added a graph visualization to @DavidSherret's amazing TypeScript AST Viewer. It's live now and very fun to play with! Edges go backwards in execution order.
ts-ast-viewer.com/#code/GYVw…
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