You’re better off using Exceptions

Exception handling is an error management paradigm that has often been met with criticism. Such criticisms typically revolve around scoping considerations, exceptions-as-control-flow abuse or even the assertion that exceptions are really just a type safe version of goto. To an extent, these seem like valid concerns but it is not within the scope of this article to address those per se.

Such concerns resonate particularly well within FP communities, often taken to the extreme: we should reject exceptions altogether, since code that throws is necessarily impure. In the F# community, this opinion is in part realized by advocating alternatives like result types and railway-oriented programming. In essence, these approaches follow the Either monad found in Haskell, but often intentionally avoiding the use of do notation/computation expressions (since that’s just interpreted exception semantics).

The TL;DR version of the approach is that we define a union type for results that looks…