/**
 * Get first item of an array
 * @param array Array to get first item from
 * @returns First item of `array`
 */
export declare const head: <Head>(array: readonly [Head, ...any[]]) => Head;
/**
 * Get first item of an array
 * @param array Array to get first item from
 * @param def Value to return should `array` is found empty
 * @returns First item of `array` if it's not empty, or `def` otherwise
 */
export declare const headOr: <Item, Default>(array: readonly Item[], def: Default) => Item | Default;
/**
 * Get first item of an array
 * @param array Array to get first item from
 * @returns First item of `array` if it's not empty, or `undefined` otherwise
 */
export declare const headOrUndefined: <Item>(array: readonly Item[]) => Item | undefined;