import { CreatePersistentConfigInterface, Persistent, PersistentKey } from '../storages';
import type { EnhancedState } from './state.enhanced';
export declare class StatePersistent<ValueType = any> extends Persistent {
    state: () => EnhancedState;
    onMigrate?: (value: any) => ValueType;
    onSave?: (value: ValueType) => any;
    static storeValueSideEffectKey: string;
    /**
     * Internal Class for managing the permanent persistence of a State.
     *
     * @internal
     * @param state - State to be persisted.
     * @param config - Configuration object
     */
    constructor(state: EnhancedState<ValueType>, config?: CreateStatePersistentConfigInterface<ValueType>);
    /**
     * Loads the persisted value into the State
     * or persists the State value in the corresponding Storage.
     * This behaviour depends on whether the State has been persisted before.
     *
     * @internal
     */
    initialLoading(): Promise<void>;
    /**
     * Loads the State from the corresponding Storage
     * and sets up side effects that dynamically update
     * the Storage value when the State changes.
     *
     * @internal
     * @param storageItemKey - Storage key of the to load State Instance.
     * | default = Persistent.key |
     * @return Whether the loading of the persisted State Instance and the setting up of the corresponding side effects was successful.
     */
    loadPersistedValue(storageItemKey?: PersistentKey): Promise<boolean>;
    /**
     * Persists the State in the corresponding Storage
     * and sets up side effects that dynamically update
     * the Storage value when the State changes.
     *
     * @internal
     * @param storageItemKey - Storage key of the to persist State Instance.
     * | default = Persistent.key |
     * @return Whether the persisting of the State Instance and setting up of the corresponding side effects was successful.
     */
    persistValue(storageItemKey?: PersistentKey): Promise<boolean>;
    /**
     * Sets up side effects to keep the Storage value in sync
     * with the current State value.
     *
     * @internal
     * @param storageItemKey - Storage key of the persisted State Instance.
     * | default = Persistent.key |
     */
    setupSideEffects(storageItemKey?: PersistentKey): void;
    /**
     * Removes the State from the corresponding Storage.
     * -> State is no longer persisted
     *
     * @internal
     * @param storageItemKey - Storage key of the to remove State Instance.
     * | default = Persistent.key |
     * @return Whether the removal of the persisted State Instance was successful.
     */
    removePersistedValue(storageItemKey?: PersistentKey): Promise<boolean>;
    /**
     * Formats the specified key so that it can be used as a valid Storage key
     * and returns the formatted variant of it.
     *
     * If no formatable key (`undefined`/`null`) was provided,
     * an attempt is made to use the State identifier key as Storage key.
     *
     * @internal
     * @param key - Storage key to be formatted.
     */
    formatKey(key: PersistentKey | undefined | null): PersistentKey | undefined;
    /**
     * Rebuilds Storage value based on the current State value.
     *
     * @internal
     * @param state - State whose current value to be applied to the Storage value.
     * @param storageItemKey - Storage key of the persisted State Instance.
     * | default = Persistent.key |
     * @param config - Configuration object
     */
    rebuildStorageSideEffect(state: EnhancedState<ValueType>, storageItemKey: PersistentKey, config?: {
        [key: string]: any;
    }): void;
}
export interface CreateStatePersistentConfigInterface<ValueType = any> extends CreatePersistentConfigInterface {
    /**
     * Method used to format the loaded value before migrating it into the State.
     * @default undefined
     */
    onMigrate?: (value: any) => ValueType;
    /**
     * Method used to format the to persist value before persisting it into the external storage.
     * @default undefined
     */
    onSave?: (value: ValueType) => any;
}