declare class Optional<T> {
    private static readonly EMPTY;
    private readonly value;
    constructor(value: T | undefined);
    /**
     * Retrieves the value if it's present, otherwise returns undefined.
     * @returns The value if present, otherwise undefined.
     */
    get(): T | undefined;
    /**
     * Checks if the value is present.
     * @returns True if the value is present, false otherwise.
     */
    isPresent(): boolean;
    /**
     * Retrieves the value if it's present, otherwise returns a specified default value.
     * @param other The default value to return if the value is absent.
     * @returns The value if present, otherwise the specified default value.
     */
    orElse(other: T): T;
    /**
     * Maps the value to a new value if present, otherwise returns an empty Optional.
     * @param mapper A function to transform the value.
     * @returns An Optional containing the transformed value if present, otherwise an empty Optional.
     */
    map<U>(mapper: (value: T) => U): Optional<U>;
    /**
     * Maps the value to a new Optional if present, otherwise returns an empty Optional.
     * Then applies a function to the value and flattens the result.
     * @param mapper A function to transform the value and return an Optional.
     * @returns An Optional containing the transformed value if present, otherwise an empty Optional.
     */
    flatMap<U>(mapper: (value: T) => Optional<U>): Optional<U>;
    /**
     * Applies a function to the value if present, otherwise does nothing.
     * @param consumer A function to apply to the value if present.
     */
    ifPresent(consumer: (value: T) => void): void;
    /**
     * Filters the value based on a predicate function.
     * @param predicate A function to test the value.
     * @returns An Optional containing the value if it passes the predicate, otherwise an empty Optional.
     */
    filter(predicate: (value: T) => boolean): Optional<T>;
    /**
     * Returns an empty Optional.
     * @returns An empty Optional instance.
     */
    static empty<T>(): Optional<T>;
    /**
     * Returns a new Optional with a value if it's present, otherwise an empty Optional.
     * @param value The value to wrap.
     * @returns An Optional containing the value if not undefined, otherwise an empty Optional.
     */
    static of<T>(value: T | undefined): Optional<T>;
    static ofNullable<T>(value: T | undefined | null): Optional<T>;
}
export default Optional;