diff --git a/lib/quickjs/qjs_typedefs.dart b/lib/quickjs/qjs_typedefs.dart
index 8b29b1c..5247f0f 100644
--- a/lib/quickjs/qjs_typedefs.dart
+++ b/lib/quickjs/qjs_typedefs.dart
@@ -4,17 +4,17 @@ import 'package:flutter_js/quickjs/utf8_null_terminated.dart';
 
 class JSContext extends Struct {
   @Uint8()
-  external int? char;
+  external int char;
 }
 
 class JSRuntime extends Struct {
   @Uint8()
-  external int? char;
+  external int char;
 }
 
 class JSValueConst extends Struct {
   @Uint8()
-  external int? char;
+  external int char;
 }
 
 const int JS_EVAL_TYPE_GLOBAL = 0;
diff --git a/lib/quickjs/utf8_null_terminated.dart b/lib/quickjs/utf8_null_terminated.dart
index ef21039..e721cdd 100644
--- a/lib/quickjs/utf8_null_terminated.dart
+++ b/lib/quickjs/utf8_null_terminated.dart
@@ -6,7 +6,7 @@ import 'package:ffi/ffi.dart';
 
 class Utf8NullTerminated extends Struct {
   @Uint8()
-  external int? char;
+  external int char;
 
   static Pointer<Utf8NullTerminated> toUtf8(String s) {
     final bytes = Utf8Encoder().convert(s);
@@ -25,7 +25,7 @@ class Utf8NullTerminated extends Struct {
     while (true) {
       final char = ptr.elementAt(len++).ref.char;
       if (char == 0) break;
-      bytes.add(char!);
+      bytes.add(char);
     }
     return Utf8Decoder().convert(bytes);
   }