```fun fetchById id String = Either catch onApiError id retu kotlinlang #arrow

```fun fetchById(id: String?) = Either.catch(::onA...

jean

11/26/2021, 7:52 AM

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fun fetchById(id: String?) = Either.catch(::onApiError) {
    id ?: return Either.Left(InOrderError.ApiError)
    ...
}

is there an nicer way to guard the nullability of Id in this case? I found

left()

but it doesn’t let me pass a type of error

simon.vergauwen

11/26/2021, 8:30 AM

Inside

either { }

you can use

ensureNotNull

❤️ 1

simon.vergauwen

11/26/2021, 8:30 AM

There is also

leftIfNull { }

simon.vergauwen

11/26/2021, 8:31 AM

Copy code

Either.catch(::onApiError).leftIfNull { InOrderError.ApiError }

jean

11/26/2021, 9:24 AM

thanks 🙂