import { Collection } from './collection.js';
import { Either } from './either.js';
import { ArrayIterable } from './array-iterable.js';
import { HashSet } from './hashset.js';
import { HashMap } from './hashmap.js';
import { Mappable } from './mappable.js';
export interface OptionMatch<A, T> {
    some: (value: A) => T;
    none: () => T;
}
export declare abstract class Option<A> extends ArrayIterable<A, Option<A>> implements Mappable<A> {
    abstract readonly get: A;
    static when<A>(cond: boolean): (a: () => A) => Option<A>;
    static useless<A>(cond: boolean): (a: () => A) => Option<A>;
    protected fromArray(array: A[]): Option<A>;
    exists(p: (value: A) => boolean): boolean;
    filter(p: (value: A) => boolean): Option<A>;
    filterNot(p: (value: A) => boolean): Option<A>;
    map<B>(f: (item: A) => B): Option<B>;
    flatMap<B>(p: (value: A) => Option<B>): Option<B>;
    mapPromise<B>(f: (v: A) => Promise<B>): Promise<Option<B>>;
    flatMapPromise<B>(f: (item: A) => Promise<Mappable<B>>): Promise<Mappable<B>>;
    foldValue<B>(ifEmpty: () => B): (f: (_: A) => B) => B;
    forall(p: (_: A) => boolean): boolean;
    foreach(f: (_: A) => void): void;
    getOrElse(f: () => A): A;
    getOrElseValue(other: A): A;
    getOrElseThrow(error: () => Error): A;
    contains<A1 extends A>(x: A1): boolean;
    get isDefined(): boolean;
    orElse(alternative: () => Option<A>): Option<A>;
    orElseValue(alternative: Option<A>): Option<A>;
    get orNull(): A | null;
    get orUndefined(): A | undefined;
    get toCollection(): Collection<A>;
    toRight<X>(left: () => X): Either<X, A>;
    toLeft<X>(right: () => X): Either<A, X>;
    get toArray(): A[];
    get toSet(): HashSet<A>;
    match<T>(matcher: OptionMatch<A, T>): T;
    toMap<K, V>(mapper: (item: A) => [K, V]): HashMap<K, V>;
}
export declare class Some<A> extends Option<A> {
    private readonly value;
    constructor(value: A);
    get get(): A;
    get isEmpty(): boolean;
}
export declare class None<A> extends Option<A> {
    get get(): A;
    get isEmpty(): boolean;
}
export declare function option<A>(value: A | null | undefined): Option<A>;
export declare function some<A>(value: A): Some<A>;
export declare const none: Option<any>;