/**
 * Utility class for managing local storage with change detection capabilities.
 * It is used in CometChatIncomingCall component.
 */
export declare class StorageUtils {
    private static isWindowListenerAttached;
    private static storageKeyToRemove;
    private static handleBeforeUnload;
    /**
     * Attaches a callback function to the `storage` event, which is triggered when storage changes occur.
     * @param {EventListenerOrEventListenerObject} callback - The function to be called when the storage event is fired. This function will receive the storage event as an argument.
     */
    static attachChangeDetection: (callback: EventListenerOrEventListenerObject) => void;
    /**
     * Detaches a previously attached callback function from the `storage` event.
     * @param {EventListenerOrEventListenerObject} callback - The function that was previously attached to the storage event. This function will be removed from the event listeners.
     */
    static detachChangeDetection: (callback: EventListenerOrEventListenerObject) => void;
    /**
     * Stores a value in local storage under the specified key.
     * @param {string} storageKey - The key under which the value will be stored.
     * @param {string} storageValue - The value to be stored in local storage. It will be converted to a JSON string.
     */
    static setItem: (storageKey: string, storageValue: string | CometChat.Call) => void;
    /**
     * Retrieves a value from local storage by its key.
     * @param {string} storageKey - The key of the item to be retrieved from local storage.
     * @returns {string} The value stored in local storage under the specified key, parsed from JSON. Returns `null` if the key does not exist.
     */
    static getItem: (storageKey: string) => any;
    /**
     * Removes an item from local storage by its key.
     * @param {string} storageKey - The key of the item to be removed from local storage.
     */
    static removeItem: (storageKey: string) => void;
}