Handling Type Errors in Safe Data Transformation with TypeScript
I have a type error that's probably due to me doing something wrong.
I'm trying to do some safe data transformation. At the first line I've validated that
The problem with this is that the type of the value becomes:
I guess my broader question is how do I pipe these sort of data transformations and collect the
I'm trying to do some safe data transformation. At the first line I've validated that
query.results.rows is an Array<Schema.Unknown> and I expect it to have a single item at this point, but I don't know so I wrap it in an Option, then I want to to decode it to a particular row type, so I do a match on the option and, if it's some it becomes the EitherSchema.decode call, or if none, I turn it into an Either.left. The problem with this is that the type of the value becomes:
Either.Either<never, string> | Either.Either<{...}, ParseError> so the type is the union of my branch types, and then when I map over it the value becomes never | {...} and typescript complins.I guess my broader question is how do I pipe these sort of data transformations and collect the
left side, because my first attempt when I tried to use map most of the time resulted in me having nested Either or an Either nested in an Option which doesn't feel great. I hope this makes sense 
