import type { Optic, TryA, TryT, A, B, S, T } from './optic.js';
import type { ArrayExpected, ArrayOfExpected } from './errors.js';
interface FilterA<Item> extends A {
    0: TryA<this, S<this> extends Item[] ? Item[] : ArrayOfExpected<Item, S<this>>>;
}
interface FilterNarrowA<Item, Narrowed extends Item> extends A {
    0: TryA<this, S<this> extends Item[] ? Narrowed[] : ArrayOfExpected<Item, S<this>>>;
}
interface FilterT<Item> extends T {
    0: TryT<this, S<this> extends Item[] ? B<this> extends any[] ? S<this> | B<this> : ArrayExpected<B<this>> : ArrayOfExpected<Item, S<this>>>;
}
export type Filter<Item> = Optic<'Lens', FilterA<Item>, FilterT<Item>>;
export type FilterNarrow<Item, Narrowed extends Item> = Optic<'Lens', FilterNarrowA<Item, Narrowed>, FilterT<Item>>;
export declare function filter<Item, Narrowed extends Item>(pred: (v: Item) => v is Narrowed): FilterNarrow<Item, Narrowed>;
export declare function filter<Item>(pred: (v: Item) => boolean): Filter<Item>;
export {};