undefined | Better HN

0 pointshudon8y ago0 comments

You're just rewording what I said. The coder can simply ignore that string or make it empty, which can lead to a runtime failure if another module depends on a value being returned (think a runtime failure from a non-exhaustive pattern match). If they were a lazy coder in TypeScript, they'll be lazy in Elm (:

So, no, what I said is not "completely false"

0 comments

Exolon8y ago

I would dispute the idea that "if they were a lazy coder in TypeScript, they'll be lazy in Elm". The fact that Elm forces you to at least think for a moment about how handle the failure case is a good thing. Even if you're inclined to take the path of least resistance, as probably most of us programmers are, what does that actually look like?

You have one case branch that looks like:

  GotUserList (Ok userList) -> ...

and another that looks like:

  GotUserList (Err _) -> ...

Since we need to pattern match on both types of the Result structure in our update cycle, there isn't really an opportunity to implicitly gloss over a failure to parse. Of course you can try to make the decoder super permissive, but this is harder than doing it the right way. If you're REALLY lazy, you can throw in "Debug.crash" in the failure case, but there's no general solution for throwing grenades at your foot :D

j / k navigate · click thread line to collapse