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TypeScript types can run DOOM

TypeScript types can run DOOM on HackerTube: recommended by 1 Hacker News commenter across 1 month, 2025.

Michigan TypeScript

demo · evergreen

Open on YouTube

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.

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.

people recommended it
1
separate months
1
strong recommendations
0
discussed on HN
2025
“I must link this wonderful video about TypeScript types running... DOOM.”
— drej, Aug 2025, in “A parser for TypeScript types, written in TypeScript types”

What HN commenters said

3 Hacker News comments link this video. Each one links back to its thread.

drejAug 2025Recommends

For those not familiar with this kind of computing challenges, I must link this wonderful video about TypeScript types running... DOOM. ▶ this video

in “A parser for TypeScript types, written in TypeScript types” · View on HN

ninetyninenineSep 2025Cites it

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 subset. Think about it. If you have a function: def add(x: int, y: int) -> int How would you verify this program is 100% correct? You have to test every possible combination of x, y and add(x, y). But instead you test like 3 or 4 possibilities in your unit tests and this helps with the overall safety of the program because of statistical sampling. If a small sample of the logic is correct, it says something about the entire population of the logic.. Types on the other hand prove your program correct. def add(x: int, y: int) -> int: return x + y If the above is type checked, your program is proven correct for ALL possible types. If those types are made more advanced via being programmable, then it becomes possible for type checking to prove your ENTIRE program correct. Imagine: def add<A: addabl

in “Python developers are embracing type hints” · View on HN

stuaxoMar 2025Cites it

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

in “A 10x Faster TypeScript” · View on HN

Topics & tags

Programming language designWeb developmenttypescriptdoomtype-level programmingturing completewasm