import { DataStoreEngine, type DataStoreData, type DataStoreEngineDSOptions, type SerializableVal } from "@sv443-network/coreutils";
/** Options for the {@linkcode GMStorageEngine} class */
export type GMStorageEngineOptions = {
    /**
     * Specifies the necessary options for storing data.  
     * - ⚠️ Only specify this if you are using this instance standalone! The parent DataStore will set this automatically.  
     */
    dataStoreOptions?: DataStoreEngineDSOptions<DataStoreData>;
};
/**
 * Storage engine for the {@linkcode DataStore} class that uses GreaseMonkey's `GM.getValue` and `GM.setValue` functions.  
 *  
 * - ⚠️ Requires the grants `GM.getValue`, `GM.setValue`, `GM.deleteValue`, and `GM.listValues` in your userscript metadata.  
 * - ⚠️ Don't reuse engine instances, always create a new one for each {@linkcode DataStore} instance.  
 */
export declare class GMStorageEngine<TData extends DataStoreData> extends DataStoreEngine<TData> {
    protected options: GMStorageEngineOptions;
    /**
     * Creates an instance of `GMStorageEngine`.  
     *  
     * - ⚠️ Requires the grants `GM.getValue`, `GM.setValue`, `GM.deleteValue`, and `GM.listValues` in your userscript metadata.  
     * - ⚠️ Don't reuse engine instances, always create a new one for each {@linkcode DataStore} instance.  
     */
    constructor(options?: GMStorageEngineOptions);
    /** Fetches a value from persistent storage */
    getValue<TValue extends SerializableVal = string>(name: string, defaultValue: TValue): Promise<string | TValue>;
    /** Sets a value in persistent storage */
    setValue<TValue extends SerializableVal = string>(name: string, value: TValue): Promise<void>;
    /** Deletes a value from persistent storage */
    deleteValue(name: string): Promise<void>;
    /** Deletes all values from GM storage. Use with caution! */
    deleteStorage(): Promise<void>;
}