10 replies

Type narrowing on `yield*` early-return

One thing I appreciate about

Effect.gen

Effect.gen

Effect.gen

Effect.gen is "early return" by yielding an error. Eg.

const maybeValue = ...;
if (Option.isNone(maybeValue)) yield* new ErrorXYZ();
// this is not executed

const maybeValue = ...;
if (Option.isNone(maybeValue)) yield* new ErrorXYZ();
// this is not executed

const maybeValue = ...;
if (Option.isNone(maybeValue)) yield* new ErrorXYZ();
// this is not executed

const maybeValue = ...;
if (Option.isNone(maybeValue)) yield* new ErrorXYZ();
// this is not executed

This is great, specially coming from

fp-ts

fp-ts

fp-ts

fp-ts where

Option.match

Option.match

Option.match

Option.match forced the indentation of the main path under

onSome

onSome

onSome

onSome.

I'm wondering about the best way to go about this. Specifically

maybeValue

maybeValue

maybeValue

maybeValue above is not narrowed to

Option.Some<...>

Option.Some<...>

Option.Some<...>

Option.Some<...>, its type is

Option.Option<...>

Option.Option<...>

Option.Option<...>

Option.Option<...>. I've found a few alternatives but none I'm fully satisfied with.