Исправлен баг в валидации at декодеров

decoder/index.ts

@@ -513,7 +513,7 @@ export function doValidate<A>(decoder: Decoder<A>, value: unknown): Either<Probl
     let iter = value as any;
     decoder._path.forEach(k => DecoderBase.path.push(k + ''));
     for (let i in decoder._path) {
-      if (iter === undefined || !iter.hasOwnProperty(decoder._path[i])) {
+      if (!iter || !iter.hasOwnProperty(decoder._path[i])) {
         iter = undefined;
         break;
       }