export interface FS {
    exists: (filepath: string) => Promise<boolean>;
    readFile: (filepath: string) => Promise<string>;
    existsSync: (filepath: string) => boolean;
    readFileSync: (filepath: string) => string;
    resolve: (root: string, file: string, ext: string) => string;
    fallback?: (file: string) => string | undefined;
}