Dan Vanderkam 🦋 (@danvdk) / X

Dan Vanderkam 🦋

1,326 posts

Dan Vanderkam 🦋

@danvdk

Independent software developer, formerly @sidewalklabs and Google. Author of Effective TypeScript, now in its 2nd edition (May 2024): amzn.to/3UjPrsK

Hudson Valley, NY

effectivetypescript.com

Joined February 2009

Pinned
Dan Vanderkam 🦋
@danvdk
May 9, 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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Dan Vanderkam 🦋
@danvdk
Sep 4, 2020
Another use of @typescript 4.1's template literal types: extracting the URL parameters from an express route. Pretty amazing you can do this in the type system! typescriptlang.org/play?ts=4.1.0-…
Dan Vanderkam 🦋
@danvdk
Feb 21, 2024
Put up my second #TypeScript PR! It allows the type checker to infer "type predicates" when a function returns a boolean that's tied to a refinement on one of its parameters. I have no idea if it'll be accepted, but I sure learned a lot implementing it! github.com/microsoft/Type…
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Dan Vanderkam 🦋
@danvdk
Aug 1, 2022
New Effective #TypeScript blog post: a command to visualize what TypeScript is compiling using a treemap (the results may surprise you!). Or: how I found out I was compiling 80+ MB of types for Google APIs that I wasn't using. effectivetypescript.com/2022/07/30/tre…
Dan Vanderkam 🦋
@danvdk
May 21, 2015
I’m excited to launch oldnyc.org! Browse 40,000 mapped historic photos of #NYC from the @nypl
Dan Vanderkam 🦋
@danvdk
Jul 29, 2023
Recommendation update: use knip to find dead code, types and dependencies in your @typescript ✂️
effectivetypescript.com
Effective TypeScript › Recommendation Update: ✂️ Use knip to detect dead code and types
TL;DR: ts-prune is in maintenance mode. Use knip to find dead code instead. It's great!
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Dan Vanderkam 🦋
@danvdk
Nov 12, 2019
I wrote a book! Happy to announce that _Effective TypeScript: 62 Specific Ways to Improve Your TypeScript_ is now available for purchase. I learned a lot writing it and I hope you'll have the same experience reading it. amazon.com/Effective-Type…
Dan Vanderkam 🦋
@danvdk
Mar 25, 2024
After using TypeScript for 8+ years, I had a mind-blowing realization: type inference is implemented completely backwards from how I think about it! Read on for the "missing manual" on Flow Nodes and TS type inference internals.
effectivetypescript.com
Effective TypeScript › Flow Nodes: How Type Inference Is Implemented
If a variable gets a type but no one looks at it, does it really get a type at all? This post looks at how type inference is implemented in the TypeScript compiler. It's of some interest to anyone...
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Dan Vanderkam 🦋
@danvdk
Feb 28, 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/GYVwdgxg…
9.5K
Dan Vanderkam 🦋
@danvdk
Apr 16, 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
Effective TypeScript › The Making of a TypeScript Feature: Inferring Type Predicates
Over the past few months I became a TypeScript contributor and implemented a new feature, type predicate inference, that should be one of the headliners for TypeScript 5.5. This post tells the story...
6.6K
Dan Vanderkam 🦋
@danvdk
Feb 3, 2021
Do you write about @typescript? These four words are my pet peeves. Please avoid them if you can!
effectivetypescript.com
Effective TypeScript › Four words to avoid in TypeScript writing
I've written many words about TypeScript and I'm sure I've read even more. Here are four words that make me cringe every time I see them. If you write about TypeScript, please steer clear of these!
Dan Vanderkam 🦋
@danvdk
Dec 25, 2022
All I want for Christmas is these seven @TypeScript features 🎄🎄🎄
effectivetypescript.com
Effective TypeScript › All I Want for Christmas Is… These Seven TypeScript Improvements
It's Christmastime and I've been happily working through this year's Advent of Code in Deno (look forward to a blog post in the new year). What with all the presents, it's a good time to think about...
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Dan Vanderkam 🦋
@danvdk
Feb 25, 2022
Which of these would you rather show your users when they call a function in @TypeScript? As a library writer, you do have some control! Read more about the strange world of type display in the latest Effective TypeScript blog post: effectivetypescript.com/2022/02/25/gen…
Dan Vanderkam 🦋
@danvdk
Oct 30, 2023
A quibble with @mattpocockuk's excellent writeup totaltypescript.com/type-vs-interf…: I'd call the "implicit index signature" for type a bug and a good reason to use interface instead because it can lead to unsoundness: typescriptlang.org/play?#code/MYe…
Type vs Interface: Which Should You Use?
From totaltypescript.com
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