type empty = null | undefined;
export declare abstract class Option<T> {
    abstract get(): T;
    abstract expect(err: Error): T;
    abstract orElse(fn: () => T): T;
    abstract orDefault(t: T): T;
    abstract map<Y>(fn: (a: T) => Y): Option<Y>;
    abstract filter(fn: (a: T) => boolean): Option<T>;
    abstract or(another: Option<T>): Option<T>;
    abstract ifPresent(fn: (t: T) => void): void;
    abstract isPresent(): boolean;
    isAbsent(): boolean;
    static none<Y>(): None<Y>;
    static some<Y>(value: Y): Some<Y>;
    static fromNullable<Y>(valueOrNull: Y | empty): None<Y> | Some<Y & {}>;
}
export declare class Some<T> extends Option<T> {
    value: T;
    constructor(t: T);
    get(): T;
    expect(_err: Error): T;
    orElse(_fn: () => T): T;
    map<Y>(fn: (a: T) => Y): Option<Y>;
    filter(fn: (a: T) => boolean): Option<T>;
    orDefault(_t: T): T;
    or(another: Option<T>): Option<T>;
    ifPresent(fn: (t: T) => void): void;
    isPresent(): boolean;
}
export declare class None<T> extends Option<T> {
    get(): T;
    expect(err: Error): T;
    orElse(fn: () => T): T;
    map<Y>(fn: (a: T) => Y): Option<Y>;
    filter(fn: (a: T) => boolean): Option<T>;
    orDefault(t: T): T;
    or(another: Option<T>): Option<T>;
    ifPresent(fn: (t: T) => void): void;
    isPresent(): boolean;
}
export {};