/**
 * Returns the index of the first matching element.
 *
 * @param array - The array to find element index in
 * @param matcher - The function that returns true if element satisfies a condition
 * @returns An element that satisfies the condition
 *
 * @category Array
 * @public
 */
export default function findIndex<ElementType>(array: Array<ElementType>, matcher: (element: ElementType) => boolean): number | -1;