import { Option } from './option';
/**
 * None is a singleton class that represents emptiness.  It signals that a value that may not exist
 * doesn't exist.
 */
declare class None_<A> implements Option<A> {
    static readonly INSTANCE: None_<never>;
    readonly isDefined: boolean;
    readonly isEmpty: boolean;
    private constructor();
    equals<B>(other: Option<B>): boolean;
    filter(predicate: (value: A) => boolean): Option<A>;
    filterNot(predicate: (value: A) => boolean): Option<A>;
    flatMap<B>(flatMapper: (value: A) => Option<B>): Option<B>;
    foreach(run: (value: A) => void): void;
    get(): A;
    getOrElse<B, A extends B>(this: None_<A>, defaultValue: () => B): B;
    map<B>(mapper: (value: A) => B): Option<B>;
    match<B>(matcher: {
        Some: (a: A) => B;
        None: () => B;
    }): B;
    orElse<B, A extends B>(this: None_<A>, alternative: () => Option<B>): Option<B>;
}
declare const instance: None_<never>;
export { None_, instance as None };