import { ObservableLike, Subscription } from '@dws/muster-observable';
import { GraphNode, NodeDefinition, StatefulGraphNode, StatefulNodeType } from '../../types/graph';
/**
 * An instance of the [[stateful]] node.
 * See the [[stateful]] documentation to find out more.
 */
export interface ExternalStatefulNode<V> extends StatefulGraphNode<'stateful', ExternalStatefulNodeProperties<V>, ExternalStatefulNodeState, ExternalStatefulNodeData> {
}
/**
 * A definition of the [[stateful]] node.
 * See the [[stateful]] documentation to find out more.
 */
export interface ExternalStatefulNodeDefinition<V> extends NodeDefinition<'stateful', ExternalStatefulNodeProperties<V>, ExternalStatefulNodeState, ExternalStatefulNodeData> {
    update(value: V): void;
}
export interface ExternalStatefulNodeProperties<V> {
    valueStream: ObservableLike<V>;
}
export interface ExternalStatefulNodeState {
    currentValue: NodeDefinition | GraphNode;
}
export interface ExternalStatefulNodeData {
    subscription: Subscription | undefined;
}
/**
 * The implementation of the [[stateful]] node.
 * See the [[stateful]] documentation to learn more.
 */
export declare const ExternalStatefulNodeType: StatefulNodeType<'stateful', ExternalStatefulNodeProperties<any>, ExternalStatefulNodeState>;
/**
 * Creates a new instance of a [[stateful]] node, which is useful when you need to create a graph node that can be changed
 * from outside Muster. It works in the same way as a [[fromStream]] with the
 * `BehaviourSubject` from RxJS.
 *
 *
 * @example **Simple stateful node**
 * ```ts
 * import muster, { computed, ref, stateful } from '@dws/muster';
 *
 * const isOffline = stateful(false);
 * const app = muster({
 *   isOffline,
 *   status: computed([ref('isOffline')], (isOffline) =>
 *     isOffline ? 'Offline' : 'Online',
 *   ),
 * });
 *
 * app.resolve(ref('status')).subscribe((status) => {
 *   console.log(status);
 * });
 *
 * console.log('Changing isOffline to true');
 * isOffline.update(true);
 *
 * // Console output:
 * // Online
 * // Changing isOffline to true
 * // Offline
 * ```
 * This example shows how to use a [[stateful]] to send values to Muster.
 */
export declare function stateful<V>(initialValue: V): ExternalStatefulNodeDefinition<V>;
export declare function isStatefulNodeDefinition(value: NodeDefinition): value is ExternalStatefulNodeDefinition<any>;