import { Observable } from 'rxjs';
import type { NormalRequest, ModuleDescription, RelativeResolverOptions } from '../interface/resolver';
/**
 * try to load description file as json, pass through payload, take the highest priority description file
 */
export declare function pickDescriptionFile(request: NormalRequest, fs: RelativeResolverOptions['fs'], descriptionFiles: RelativeResolverOptions['descriptionFiles']): Observable<ModuleDescription>;
/**
 * compose main field into request
 */
export declare function pickMainField(request: NormalRequest, descriptions: ModuleDescription, mainFields: string[]): Observable<NormalRequest>;