import { ChildKey, NodeDefinition, NodeLike, StaticGraphNode, StaticNodeDefinition, StaticNodeType } from '../../types/graph';
import { ErrorFallbackGenerator } from './if-error';
import { KeyNodeDefinition } from './key';
/**
 * An instance of the [[catchError]] node.
 * See the [[catchError]] documentation to find out more.
 */
export interface CatchErrorNode extends StaticGraphNode<'catch-error', CatchErrorNodeProperties> {
}
/**
 * A definition of the [[catchError]] node.
 * See the [[catchError]] documentation to find out more.
 */
export interface CatchErrorNodeDefinition extends StaticNodeDefinition<'catch-error', CatchErrorNodeProperties> {
}
export interface CatchErrorNodeProperties {
    fallbackGenerator: ErrorFallbackGenerator;
    target: KeyNodeDefinition;
}
/**
 * The implementation of the [[catchError]].
 * See the [[catchError]] documentation to learn more.
 */
export declare const CatchErrorNodeType: StaticNodeType<'catch-error', CatchErrorNodeProperties>;
/**
 * Creates a new instance of a [[catchError]] node, which is a type of a [[NodeDefinition]] used inside a [[query]]
 * to indicate that a given part of the query can resolve to an error, and in that case it should be replaced with
 * a given fallback value.
 *
 * @example **Fallback value when branch errors**
 * ```javascript
 * import muster, { catchError, error, key, query, root, value } from '@dws/muster';
 *
 * const app = muster({
 *   user: error('Some reason why user can`t be loaded'),
 * });
 *
 * await app.resolve(query(root(), {
 *   user: catchError(value('Could not load user'), {
 *     firstName: key('firstName'),
 *     lastName: key('lastName'),
 *   }),
 * })); // === 'Could not load user'
 * ```
 */
export declare function catchError(fallback: ErrorFallbackGenerator | NodeDefinition | NodeLike, target: KeyNodeDefinition | ChildKey): CatchErrorNodeDefinition;
export declare function isCatchErrorNodeDefinition(value: NodeDefinition): value is CatchErrorNodeDefinition;