Comment by cubefox
10 hours ago
> I agree that this can be nice when done right (Clojure),
I don't think Clojure has untagged union types like TypeScript or Scala.
> but null is a high price to pay for this convenience.
Why would it be? Untagged unions prevent null pointer errors just as much as option types do, only they don't have the discussed disadvantages of option types.
I was thinking about a general experience of working with null/nil. Clojure has nil punning which makes sense in the context of the language (lisp variant) and can be nice to work with.
The null is a high price to pay because eventually someone will make some type assertion somewhere in the TS codebase that will end up biting you. Sure, you can be diligent, but will every contributor during the lifetime of a project be?
Not sure about Scala, but I did see NullPointerException every so often, and what is the practical advice to handle them in Scala? It’s to use Option[T]
> Why would it be?
That's literally what they explain in the rest of the comment.
No, they don't reference any "high price to pay", only that they personally didn't need the advantages of untagged union types so far, and that Haskell (allegedly) has patterns that would play a similar role for libraries.