export interface Finder<R extends 'value' | 'index'> {
    (collection: readonly number[], target: number, filterMapFn?: FilterMapFn<number>): number;
    <T>(collection: readonly T[], target: number, filterMapFn: FilterMapFn<T, false>): R extends 'value' ? T : number;
}
/**
 * A type for underling functions that implement the overloaded
 * function signature `Finder`.
 *
 * This helps avoid "implicit 'any'" warnings - we don't need to define
 * these arguments over and over.
 *
 * If there's a better way to do this, please tell me!
 */
export declare type FinderNonOverloaded<R extends 'value' | 'index'> = <T>(collection: readonly T[], target: number, filterMapFn?: FilterMapFn<T>) => R extends 'value' ? T : number;
export declare type FilterMapFn<T, R extends boolean = boolean> = (value: T, context: {
    index: number;
    target: number;
    collection: readonly T[];
}) => number | R;