/**
 * Represents a queue data structure.
 * @template T The type of elements in the queue.
 * @example
 * const queue = new Queue<number>();
 * queue.enqueue(1).enqueue(2);
 * console.log(queue.dequeue()); // 1
 */
export declare class Queue<T> {
    private items;
    /**
     * Adds an item to the end of the queue.
     * @param {T} item - The item to add to the queue.
     * @returns {Queue<T>} The queue instance for chaining.
     */
    enqueue(item: T): this;
    /**
     * Removes and returns the item at the front of the queue.
     * @returns {T} The item at the front of the queue.
     * @throws {Error} If the queue is empty.
     */
    dequeue(): T;
    /**
     * Returns the number of items in the queue.
     * @returns {number} The size of the queue.
     */
    size(): number;
    /**
     * Returns the item at the front of the queue without removing it.
     * @returns {T | undefined} The item at the front of the queue, or undefined if the queue is empty.
     */
    peek(): T | undefined;
    /**
     * Checks if the queue is empty.
     * @returns {boolean} True if the queue is empty, false otherwise.
     */
    isEmpty(): boolean;
    /**
     * Checks if the queue contains a specific item.
     * @param {T} item - The item to check for.
     * @returns {boolean} True if the item is in the queue, false otherwise.
     */
    contains(item: T): boolean;
    /**
     * Creates a copy of the queue.
     * @returns {Queue<T>} A new queue instance with the same items.
     */
    copy(): Queue<T>;
    /**
     * Serializes the queue to a JSON string.
     * @returns {string} The serialized queue.
     */
    serialize(): string;
    /**
     * Deserializes a JSON string to populate the queue.
     * @param {string} data - The JSON string to deserialize.
     */
    deserialize(data: string): void;
}