[ninetyninenine]

TS sum types are actually more powerful thanks to 'as const'

These are dependent types which none of the languages above can enable. Meaning the type system can actually read values in your code and create types from the code. This is not inferring the type, this is very different.

For example:

   const PossibleStates = ["test", "me"] as const

   type SumTypeFromArray = (typeof PossibleStates)[number]

   let x: SumTypeFromArray = "this string triggers a type error as it is neither 'test' nor 'me'"

So in TS you can actually loop through possible states while in ML style languages you would have to pattern match them individually.