import { NodeDefinition, NodeLike, StatelessGraphNode, StatelessNodeDefinition, StatelessNodeType } from '../../types/graph';
/**
 * An instance of the [[log]] node.
 * See the [[log]] documentation to find out more.
 */
export interface LogNode extends StatelessGraphNode<'log', LogNodeProperties> {
}
/**
 * A definition of the [[log]] node.
 * See the [[log]] documentation to find out more.
 */
export interface LogNodeDefinition extends StatelessNodeDefinition<'log', LogNodeProperties> {
}
export interface LogNodeProperties {
    target: NodeDefinition;
}
/**
 * The implementation of the [[log]].
 * See the [[log]] documentation to learn more.
 */
export declare const LogNodeType: StatelessNodeType<'log', LogNodeProperties>;
/**
 * Creates a new instance of a [[log]] node, which is a type of a [[NodeDefinition]] used for logging a value of a
 * target node every time it emits a new value.
 *
 * @example **Log [[computed]] value**
 * ```js
 * import muster, { computed, log, ref, set, variable } from '@dws/muster';
 *
 * const app = muster({
 *   balance: variable(500),
 *   bet: variable(100),
 *   canBet: log(
 *     computed(
 *       [ref('balance'), ref('bet')],
 *       (balance, bet) => balance >= bet,
 *     ),
 *   ),
 * });
 *
 * // Just subscribe, no need to log anything as LogNode will handle that
 * app.resolve(ref('canBet')).subscribe((canBet) => {});
 *
 * await app.resolve(set('bet', 510));
 *
 * await app.resolve(set('bet', 30));
 *
 * // Console output:
 * // { input: <<computed node>>, output: value(true) }
 * // { input: <<computed node>>, output: value(false) }
 * // { input: <<computed node>>, output: value(true) }
 * ```
 */
export declare function log(target: NodeLike | NodeDefinition): LogNodeDefinition;
export declare function isLogNodeDefinition(value: NodeDefinition): value is LogNodeDefinition;