export type StorageItemMapOptions<T> = {
    area?: chrome.storage.AreaName;
    defaultValue?: T;
};
export declare class StorageItemMap<
/** Only specify this if you don't have a default value */
Base, 
/** The return type will be undefined unless you provide a default value */
Return = Base | undefined> {
    readonly prefix: `${string}:::`;
    readonly areaName: chrome.storage.AreaName;
    readonly defaultValue?: Return;
    constructor(key: string, { area, defaultValue, }?: StorageItemMapOptions<Exclude<Return, undefined>>);
    has: (secondaryKey: string) => Promise<boolean>;
    get: (secondaryKey: string) => Promise<Return>;
    set: (secondaryKey: string, value: Exclude<Return, undefined>) => Promise<void>;
    remove: (secondaryKey: string) => Promise<void>;
    /** @deprecated Only here to match the Map API; use `remove` instead */
    delete: (secondaryKey: string) => Promise<void>;
    onChanged(callback: (key: string, value: Exclude<Return, undefined>) => void, signal?: AbortSignal): void;
    private getRawStorageKey;
    private getSecondaryStorageKey;
}