import UniqueViewIdStorageOptions from './UniqueViewIdStorageOptions.js';
/**
 * A localStorage wrapper which contains logic to manage Omnitracking's unique view
 * ids lifetime.
 */
declare class UniqueViewIdStorage {
    private config;
    /**
     * Creates an instance of the storage with the passed configuration.
     *
     * @param config - Config parameters.
     */
    constructor(config?: UniqueViewIdStorageOptions);
    /**
     * Gets the unique view id associated with the url received on the key argument
     * from localStorage or null if not found/expired/does not support localStorage.
     *
     * @param key - The url string to retrieve the unique view id from.
     *
     * @returns - The associated unique view id for the key or null if not found/expired/does not support
     * localStorage.
     */
    get(key: string): string | null;
    /**
     * Sets the unique view id value of the url key in localStorage, if supported. Will
     * remove oldest entries if items limit has been reached in order to accommodate
     * the new entry.
     *
     * @param key   - The url to save the unique view id value.
     * @param value - The unique view id to save.
     *
     * @returns True if item was saved in localStorage, false otherwise.
     */
    set(key: string, value: string): boolean;
    /**
     * Removes expired entries in localStorage.
     */
    removeExpired(): void;
    /**
     * Removes oldest item from localStorage, if found.
     */
    removeOldestItem(): void;
    /**
     * Checks if the currently unique view id items stored in localStorage have hit the
     * limit specified in config.
     *
     * @returns True if the max limit of items stored in localStorage is greater or equal than the maxItems
     * config.
     */
    hasLimitReached(): boolean;
    /**
     * Check if a url key entry in localStorage has expired.
     *
     * @param key - The url key to check.
     *
     * @returns True if the expires time of the entry has been reached, false otherwise.
     */
    isExpired(key: string): boolean;
    /**
     * Auxiliary method used by set method to store the entry in localStorage.
     *
     * @param key   - The url key to save the unique view id value.
     * @param value - The unique view id value for the url key.
     */
    setItem(key: string, value: string): void;
    /**
     * Removes an item from localStorage.
     *
     * @param key - The url key to remove.
     */
    removeItem(key: string): void;
    /**
     * Checks if the runtime environment supports localStorage.
     *
     * @returns True if localStorage is supported, false otherwise.
     */
    supportsLocalStorage(): boolean;
    /**
     * Clears all UniqueViewId items from localStorage.
     */
    clear(): void;
}
export default UniqueViewIdStorage;