@lou.codes/iterables
Version:
🔁 Iterable and AsyncIterable utils
28 lines (27 loc) • 875 B
TypeScript
import type {
IsomorphicIterable,
Predicate,
Single,
Unary,
} from "@lou.codes/types";
/**
* Filters items in an iterable or asynchronous iterable against a predicate and
* returns items that evaluated to `true`.
*
* @category Asynchronous Generators
* @example
* ```typescript
* const filterEven = filter((number: number) => number % 2 === 0);
*
* iterableToArray(filterEven([1, 2, 3, 4])); // [2, 4]
* iterableToArray(filterEven([1, 3, 5, 7])); // []
* ```
* @param predicate Predicate function to evaluate each item.
* @returns Curried function with `predicate` set in context.
*/
export declare const filter: <Item, Filtered extends Item = never>(
predicate: Single<Filtered> extends Single<never> ? Unary<Item, boolean>
: Predicate<Item, Filtered>,
) => (
iterable: IsomorphicIterable<Item>,
) => Readonly<AsyncIterableIterator<Awaited<Filtered>>>;