[conistonwater]

The first one reads like somebody just found out about functional programming and functors and tried to "improve" a straightforward bunch of if statements. I can read the second program without having read the plain English description, but I definitely would prefer to have the comment for the first one. I think even in languages like Haskell I would prefer (just sometimes) to read just a straight if-elseif-elseif-else.

The whole thing about the way it's written with throwing/catching is a red herring anyway, you should just replace those with a different choice of if's. If you're feeling super adventurous, you can instead replace them with goto's, which is kinda funny; it would actually simplify the code, how often do you see that?

[jamincan]

I think part of the problem is that Typescript doesn't have support for error-as-value baked into the language and pervasive in the ecosystem, so adopting that style isn't as ergonomic as it would be in a language that does. The equivalent in Rust would be far more clear and concise due to the ? operator and Result-types being ubiquitous.