import type {
	Head,
	IsomorphicIterable,
	IsomorphicIterableItem,
	Maybe,
	ReadOnlyArray,
} from "@vangware/types";
/**
 * Get first element of an iterable or asynchronous iterable (`undefined` if
 * it is empty).
 *
 * @category Reducers
 * @example
 * ```typescript
 * head([1, 2, 3]); // 1
 * ```
 * @param iterable Iterable to get the first element from.
 * @returns First element of the iterable (`undefined` if empty).
 */
export declare const head: <Iterable_1 extends IsomorphicIterable>(
	iterable: Iterable_1,
) => Iterable_1 extends ReadOnlyArray
	? Head<Iterable_1>
	: Maybe<IsomorphicIterableItem<Iterable_1>>;