# filterMapEffect

Maps and filters elements of an Fx using an effectful function.

## Signatures

```ts
export declare const filterMapEffect: {
    <A, B, E2, R2>(f: (a: A) => Effect.Effect<Option.Option<B>, E2, R2>): <E, R>(self: Fx<A, E | E2, R>) => Fx<B, E | E2, R | R2>;
    <A, E, R, B, E2, R2>(self: Fx<A, E | E2, R>, f: (a: A) => Effect.Effect<Option.Option<B>, E2, R2>): Fx<B, E | E2, R | R2>;
};
```

## Why

`filterMapEffect` combines an Effectful decision and transformation without introducing nested
streams. `Some` emits once and `None` emits nothing. Producer callbacks are not serialized, so
overlapping Effects can complete and emit in a different order than their inputs.

## Ownership and lifetime

Each callback Effect follows its invoking producer delivery. Its failure Cause is sent to the
Sink, services remain exposed as `R2`, and no semaphore, queue, or resource is added.

## Examples

```ts
import { Effect, Option } from "effect"
import { Fx } from "@typed/fx"

const accepted = Fx.fromIterable([1, 2]).pipe(
  Fx.filterMapEffect((n) => Effect.succeed(n > 1 ? Option.some(n * 10) : Option.none()))
)
```