TypeScript types can run DOOM
Why Hacker News recommends it
HN commenters link it as a delightful example of how far TypeScript types can be pushed, since they are Turing complete.
What it is
The Michigan TypeScript group shows the Doom engine running entirely inside the TypeScript type system. It is open source, and two follow-up videos cover why and how they did it.
Recommended by 1 HN commenters across 1 different months, 2025 to 2025.
What Hacker News said
Recommends drej · 2025-08 · on “A parser for TypeScript types, written in TypeScript types”
For those not familiar with this kind of computing challenges, I must link this wonderful video about TypeScript types running... DOOM. [this video]
Cites stuaxo · 2025-03 · on “A 10x Faster TypeScript”
I'd like to see if it makes a difference to the version of DOOM that runs in the TypeScript type system. [LINK] [this video]
Cites ninetyninenine · 2025-09 · on “Python developers are embracing type hints”
Typescript types (and Idris) are Turing complete. You can actually get typescript types to run doom. [this video] Idris on the other hand is SPECIFICALLY designed so types and the program live in the same language. See the documentation intro: [LINK] THe powerful thing about these languages is that they can prove your program correct. For testing you can never verify your program to be correct. Testing is a statistical sampling technique. To verify a program as correct via tests you have to test every possible input and output combination of your program, which is impractical. So instead people write tests for a subset of the possibilities which ONLY verifies the program as correct for that subse