/**
 * A generic Queue implementation with First-In-First-Out (FIFO) behavior.
 * @template T The type of elements stored in the queue.
 */
export declare class Queue<T> {
    private items;
    /**
     * Adds an item to the end of the queue.
     * @param item The item to add to the queue.
     * @returns The new length of the queue.
     */
    enqueue(item: T): number;
    /**
     * Removes and returns the item at the front of the queue.
     * @returns The removed item, or undefined if the queue is empty.
     */
    dequeue(): T | undefined;
    /**
     * Returns the item at the front of the queue without removing it.
     * @returns The front item, or undefined if the queue is empty.
     */
    peek(): T | undefined;
    /**
     * Checks if the queue is empty.
     * @returns True if the queue has no items, false otherwise.
     */
    isEmpty(): boolean;
    /**
     * Gets the number of items in the queue.
     * @returns The queue size.
     */
    size(): number;
    /**
     * Removes all items from the queue.
     */
    clear(): void;
    /**
     * Returns all items in the queue as an array (without modifying the queue).
     * The first element in the array is the front of the queue, the last is the back.
     * @returns An array containing all queue items.
     */
    toArray(): T[];
}