diff --git a/ts/typedrequest.classes.typedresponseerror.ts b/ts/typedrequest.classes.typedresponseerror.ts
index 14df603..edea912 100644
--- a/ts/typedrequest.classes.typedresponseerror.ts
+++ b/ts/typedrequest.classes.typedresponseerror.ts
@@ -3,7 +3,7 @@ import * as plugins from './typedrequest.plugins';
 export class TypedResponseError {
   public errorText: string;
   public errorData: any;
-  constructor(errorTextArg: string, errorDataArg: any) {
+  constructor(errorTextArg: string, errorDataArg?: any) {
     this.errorText = errorTextArg;
     this.errorData = errorDataArg;
   }