/**
 * This describes the attributes and methods that a store has to support in
 * order to be used with GraphiQL. It closely resembles the `localStorage`
 * API as it is the default storage used in GraphiQL.
 */
declare type Storage = {
    /**
     * Retrieve an item from the store by its key.
     * @param key The key of the item to retrieve.
     * @returns {?string} The stored value for the given key if it exists, `null`
     * otherwise.
     */
    getItem(key: string): string | null;
    /**
     * Add a value to the store for a given key. If there already exists a value
     * for the given key, this method will override the value.
     * @param key The key to store the value for.
     * @param value The value to store.
     */
    setItem(key: string, value: string): void;
    /**
     * Remove the value for a given key from the store. If there is no value for
     * the given key this method does nothing.
     * @param key The key to remove the value from the store.
     */
    removeItem(key: string): void;
    /**
     * Remove all items from the store.
     */
    clear(): void;
    /**
     * The number of items that are currently stored.
     */
    length: number;
};
declare class StorageAPI {
    storage: Storage | null;
    constructor(storage?: Storage | null);
    get(name: string): string | null;
    set(name: string, value: string): {
        isQuotaError: boolean;
        error: Error | null;
    };
    clear(): void;
}

export { type Storage, StorageAPI };