import { EnsureBaseOptions, EnsureIsOptional, EnsureDefault } from '../ensure'; declare function ensureString(value: any, options?: EnsureBaseOptions): string; declare function ensureString(value: any, options?: EnsureBaseOptions & EnsureIsOptional): string | null; declare function ensureString(value: any, options?: EnsureBaseOptions & EnsureIsOptional & EnsureDefault): string; export default ensureString;