# provideService

Provides one concrete service to a Guard.

## Signatures

```ts
export declare const provideService: {
    <Id, S>(tag: Context.Service<Id, S>, service: S): <I, O, E, R>(guard: GuardInput<I, O, E, R>) => Guard<I, O, E, Exclude<R, Id>>;
    <I, O, E, R, Id, S>(guard: GuardInput<I, O, E, R>, tag: Context.Service<Id, S>, service: S): Guard<I, O, E, Exclude<R, Id>>;
};
```

## Why

Targeted service provision removes only the selected identifier from the Guard environment.

## Ownership and lifetime

This combinator acquires no resources and reuses the supplied service for each invocation.

## Examples

```ts
import { provideService } from "@typed/guard"
import type { Guard } from "@typed/guard"
import { Context, Effect, Option } from "effect"
const Flag = Context.Service<{ readonly enabled: boolean }>("Flag")
const requiresFlag: Guard<boolean, boolean, never, Context.Service.Identifier<typeof Flag>> = (input) => Effect.map(Effect.service(Flag), ({ enabled }) => enabled && input ? Option.some(input) : Option.none())
const guard = provideService(requiresFlag, Flag, { enabled: true })
```