true-myth VS nominal

TS doesn't do anything at runtime no, but there are some type checking libraries that could help you. I don't know what packages you're talking about in particular, but if they are IO related you can try io-ts. More generally you could also look into true-myth for Maybe types and wrap any values that come out of your packages before allowing them to be passed into your code.

Hey OP here, Wanted to share something we recently discovered in typescript. This is a way to to create haskell style Newtype using the lesser known \`symbols\` ```ts type Minutes = number type Seconds = number const minutesToSeconds = (minutes: Minutes) => minutes * 60 const seconds: Seconds = 420 // uh-oh, we can use Minutes and Seconds interchangeably minutesToSeconds(seconds) ``` Nominal types solve this problem ```ts import { Nominal, nominal } from 'nominal-types'; type Minutes = Nominal<'Minutes', number>; type Seconds = Nominal<'Seconds', number>; const minutesToSeconds = (minutes: Minutes) => minutes * 60 // You can directly type cast or use nominal.make const seconds = nominal.make(420) const minutes = 1337 as Minutes // doesn't work, yay type safety minutesToSeconds(seconds) // does work! minutesToSeconds(minutes) ``` We have some lot cooler examples https://github.com/modfy/nominal#examples You can also read more about it here: https://zackoverflow.dev/writing/nominal-and-refinement-types-typescript