diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7941b38..a2a2e57 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@
  * @LastEditTime: 2020-12-02 11:36:40
 -->
 
+## 0.3.2
+
+* fix Promise reject cannot get Exception string.
+
 ## 0.3.1
 
 * code clean up.
diff --git a/README.md b/README.md
index 1a1797e..2a85e43 100644
--- a/README.md
+++ b/README.md
@@ -100,16 +100,7 @@ To use async function in module handler, try [Run on isolate thread](#Run-on-iso
 Create a `IsolateQjs` object, pass handlers to resolving modules. Async function such as `rootBundle.loadString` can be used now to get modules:
 
 ```dart
-dynamic methodHandler(String method, List arg) {
-  switch (method) {
-    case "http":
-      return Dio().get(arg[0]).then((response) => response.data);
-    default:
-      throw Exception("No such method");
-  }
-}
 final engine = IsolateQjs(
-  methodHandler: methodHandler,
   moduleHandler: (String module) async {
     return await rootBundle.loadString(
         "js/" + module.replaceFirst(new RegExp(r".js$"), "") + ".js");
@@ -134,9 +125,9 @@ Method `close` can destroy quickjs runtime that can be recreated again if you ca
 Method `bind` can help to pass instance function to isolate:
 
 ```dart
-await setToGlobalObject("func", await engine.bind(({thisVal}) {
+await jsFunc(await engine.bind(({thisVal}) {
   // DO SOMETHING
-}))
+}));
 ```
 
 [This example](example/lib/main.dart) contains a complete demonstration on how to use this plugin.
@@ -148,5 +139,5 @@ Use js function to set dart object globally:
 
 ```dart
 final setToGlobalObject = await engine.evaluate("(key, val) => this[key] = val;");
-setToGlobalObject("channel", methodHandler);
+await setToGlobalObject("channel", methodHandler);
 ```
\ No newline at end of file
diff --git a/example/pubspec.lock b/example/pubspec.lock
index 2e79c76..0566f0c 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -75,7 +75,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.3.1"
+    version: "0.3.2"
   flutter_test:
     dependency: "direct dev"
     description: flutter
diff --git a/lib/ffi.dart b/lib/ffi.dart
index 3a4d9bd..4a07bd5 100644
--- a/lib/ffi.dart
+++ b/lib/ffi.dart
@@ -57,14 +57,14 @@ class JSTag {
 
 final DynamicLibrary _qjsLib = Platform.environment['FLUTTER_TEST'] == 'true'
     ? (Platform.isWindows
-        ? DynamicLibrary.open("test/build/Debug/ffiquickjs.dll")
+        ? DynamicLibrary.open('test/build/Debug/ffiquickjs.dll')
         : Platform.isMacOS
-            ? DynamicLibrary.open("test/build/libffiquickjs.dylib")
-            : DynamicLibrary.open("test/build/libffiquickjs.so"))
+            ? DynamicLibrary.open('test/build/libffiquickjs.dylib')
+            : DynamicLibrary.open('test/build/libffiquickjs.so'))
     : (Platform.isWindows
-        ? DynamicLibrary.open("flutter_qjs_plugin.dll")
+        ? DynamicLibrary.open('flutter_qjs_plugin.dll')
         : Platform.isAndroid
-            ? DynamicLibrary.open("libqjs.so")
+            ? DynamicLibrary.open('libqjs.so')
             : DynamicLibrary.process());
 
 /// JSValue *jsThrowInternalError(JSContext *ctx, char *message)
@@ -77,7 +77,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Pointer<Utf8>,
-    )>>("jsThrowInternalError")
+    )>>('jsThrowInternalError')
     .asFunction();
 
 Pointer jsThrowInternalError(Pointer ctx, String message) {
@@ -89,12 +89,12 @@ Pointer jsThrowInternalError(Pointer ctx, String message) {
 
 /// JSValue *jsEXCEPTION()
 final Pointer Function() jsEXCEPTION = _qjsLib
-    .lookup<NativeFunction<Pointer Function()>>("jsEXCEPTION")
+    .lookup<NativeFunction<Pointer Function()>>('jsEXCEPTION')
     .asFunction();
 
 /// JSValue *jsUNDEFINED()
 final Pointer Function() jsUNDEFINED = _qjsLib
-    .lookup<NativeFunction<Pointer Function()>>("jsUNDEFINED")
+    .lookup<NativeFunction<Pointer Function()>>('jsUNDEFINED')
     .asFunction();
 
 typedef JSChannel = Pointer Function(Pointer ctx, int method, Pointer argv);
@@ -109,7 +109,7 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsNewRuntime")
+    )>>('jsNewRuntime')
     .asFunction();
 
 class RuntimeOpaque {
@@ -147,7 +147,7 @@ final void Function(
             Void Function(
       Pointer,
       IntPtr,
-    )>>("jsSetMaxStackSize")
+    )>>('jsSetMaxStackSize')
     .asFunction();
 
 /// void jsFreeRuntime(JSRuntime *rt)
@@ -158,7 +158,7 @@ final void Function(
         NativeFunction<
             Void Function(
       Pointer,
-    )>>("jsFreeRuntime")
+    )>>('jsFreeRuntime')
     .asFunction();
 
 void jsFreeRuntime(
@@ -181,7 +181,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Pointer,
-    )>>("jsNewCFunction")
+    )>>('jsNewCFunction')
     .asFunction();
 
 /// JSContext *jsNewContext(JSRuntime *rt)
@@ -192,14 +192,14 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsNewContext")
+    )>>('jsNewContext')
     .asFunction();
 
 Pointer jsNewContext(Pointer rt) {
   var ctx = _jsNewContext(rt);
   final runtimeOpaque = runtimeOpaques[rt];
-  if (runtimeOpaque == null) throw Exception("Runtime has been released!");
-  runtimeOpaque.dartObjectClassId = jsNewClass(ctx, "DartObject");
+  if (runtimeOpaque == null) throw Exception('Runtime has been released!');
+  runtimeOpaque.dartObjectClassId = jsNewClass(ctx, 'DartObject');
   return ctx;
 }
 
@@ -211,7 +211,7 @@ final void Function(
         NativeFunction<
             Void Function(
       Pointer,
-    )>>("jsFreeContext")
+    )>>('jsFreeContext')
     .asFunction();
 
 /// JSRuntime *jsGetRuntime(JSContext *ctx)
@@ -222,7 +222,7 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsGetRuntime")
+    )>>('jsGetRuntime')
     .asFunction();
 
 /// JSValue *jsEval(JSContext *ctx, const char *input, size_t input_len, const char *filename, int eval_flags)
@@ -241,7 +241,7 @@ final Pointer Function(
       IntPtr,
       Pointer<Utf8>,
       Int32,
-    )>>("jsEval")
+    )>>('jsEval')
     .asFunction();
 
 Pointer jsEval(
@@ -273,7 +273,7 @@ final int Function(
         NativeFunction<
             Int32 Function(
       Pointer,
-    )>>("jsValueGetTag")
+    )>>('jsValueGetTag')
     .asFunction();
 
 /// void *jsValueGetPtr(JSValue *val)
@@ -284,7 +284,7 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsValueGetPtr")
+    )>>('jsValueGetPtr')
     .asFunction();
 
 /// DLLEXPORT bool jsTagIsFloat64(int32_t tag)
@@ -295,7 +295,7 @@ final int Function(
         NativeFunction<
             Int32 Function(
       Int32,
-    )>>("jsTagIsFloat64")
+    )>>('jsTagIsFloat64')
     .asFunction();
 
 /// JSValue *jsNewBool(JSContext *ctx, int val)
@@ -308,7 +308,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Int32,
-    )>>("jsNewBool")
+    )>>('jsNewBool')
     .asFunction();
 
 /// JSValue *jsNewInt64(JSContext *ctx, int64_t val)
@@ -321,7 +321,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Int64,
-    )>>("jsNewInt64")
+    )>>('jsNewInt64')
     .asFunction();
 
 /// JSValue *jsNewFloat64(JSContext *ctx, double val)
@@ -334,7 +334,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Double,
-    )>>("jsNewFloat64")
+    )>>('jsNewFloat64')
     .asFunction();
 
 /// JSValue *jsNewString(JSContext *ctx, const char *str)
@@ -347,7 +347,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Pointer<Utf8>,
-    )>>("jsNewString")
+    )>>('jsNewString')
     .asFunction();
 
 Pointer jsNewString(
@@ -370,7 +370,7 @@ final Pointer Function(
       Pointer,
       Pointer<Uint8>,
       IntPtr,
-    )>>("jsNewArrayBufferCopy")
+    )>>('jsNewArrayBufferCopy')
     .asFunction();
 
 /// JSValue *jsNewArray(JSContext *ctx)
@@ -381,7 +381,7 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsNewArray")
+    )>>('jsNewArray')
     .asFunction();
 
 /// JSValue *jsNewObject(JSContext *ctx)
@@ -392,7 +392,7 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsNewObject")
+    )>>('jsNewObject')
     .asFunction();
 
 /// void jsFreeValue(JSContext *ctx, JSValue *val, int32_t free)
@@ -407,7 +407,7 @@ final void Function(
       Pointer,
       Pointer,
       Int32,
-    )>>("jsFreeValue")
+    )>>('jsFreeValue')
     .asFunction();
 
 void jsFreeValue(
@@ -430,7 +430,7 @@ final void Function(
       Pointer,
       Pointer,
       Int32,
-    )>>("jsFreeValueRT")
+    )>>('jsFreeValueRT')
     .asFunction();
 
 void jsFreeValueRT(
@@ -451,7 +451,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Pointer,
-    )>>("jsDupValue")
+    )>>('jsDupValue')
     .asFunction();
 
 /// JSValue *jsDupValueRT(JSRuntime *rt, JSValue *v)
@@ -464,7 +464,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Pointer,
-    )>>("jsDupValueRT")
+    )>>('jsDupValueRT')
     .asFunction();
 
 /// int32_t jsToBool(JSContext *ctx, JSValueConst *val)
@@ -477,7 +477,7 @@ final int Function(
             Int32 Function(
       Pointer,
       Pointer,
-    )>>("jsToBool")
+    )>>('jsToBool')
     .asFunction();
 
 /// int64_t jsToFloat64(JSContext *ctx, JSValueConst *val)
@@ -490,7 +490,7 @@ final int Function(
             Int64 Function(
       Pointer,
       Pointer,
-    )>>("jsToInt64")
+    )>>('jsToInt64')
     .asFunction();
 
 /// double jsToFloat64(JSContext *ctx, JSValueConst *val)
@@ -503,7 +503,7 @@ final double Function(
             Double Function(
       Pointer,
       Pointer,
-    )>>("jsToFloat64")
+    )>>('jsToFloat64')
     .asFunction();
 
 /// const char *jsToCString(JSContext *ctx, JSValue *val)
@@ -516,7 +516,7 @@ final Pointer<Utf8> Function(
             Pointer<Utf8> Function(
       Pointer,
       Pointer,
-    )>>("jsToCString")
+    )>>('jsToCString')
     .asFunction();
 
 /// void jsFreeCString(JSContext *ctx, const char *ptr)
@@ -529,7 +529,7 @@ final void Function(
             Void Function(
       Pointer,
       Pointer<Utf8>,
-    )>>("jsFreeCString")
+    )>>('jsFreeCString')
     .asFunction();
 
 String jsToCString(
@@ -537,7 +537,7 @@ String jsToCString(
   Pointer val,
 ) {
   var ptr = _jsToCString(ctx, val);
-  if (ptr.address == 0) throw Exception("JSValue cannot convert to string");
+  if (ptr.address == 0) throw Exception('JSValue cannot convert to string');
   var str = Utf8.fromUtf8(ptr);
   jsFreeCString(ctx, ptr);
   return str;
@@ -553,7 +553,7 @@ final int Function(
             Uint32 Function(
       Pointer,
       Pointer<Utf8>,
-    )>>("jsNewClass")
+    )>>('jsNewClass')
     .asFunction();
 
 int jsNewClass(
@@ -581,7 +581,7 @@ final Pointer Function(
       Pointer,
       Uint32,
       IntPtr,
-    )>>("jsNewObjectClass")
+    )>>('jsNewObjectClass')
     .asFunction();
 
 /// DLLEXPORT void *jsGetObjectOpaque(JSValue *obj, uint32_t classid)
@@ -594,7 +594,7 @@ final int Function(
             IntPtr Function(
       Pointer,
       Uint32,
-    )>>("jsGetObjectOpaque")
+    )>>('jsGetObjectOpaque')
     .asFunction();
 
 /// uint8_t *jsGetArrayBuffer(JSContext *ctx, size_t *psize, JSValueConst *obj)
@@ -609,7 +609,7 @@ final Pointer<Uint8> Function(
       Pointer,
       Pointer<IntPtr>,
       Pointer,
-    )>>("jsGetArrayBuffer")
+    )>>('jsGetArrayBuffer')
     .asFunction();
 
 /// int32_t jsIsFunction(JSContext *ctx, JSValueConst *val)
@@ -622,7 +622,7 @@ final int Function(
             Int32 Function(
       Pointer,
       Pointer,
-    )>>("jsIsFunction")
+    )>>('jsIsFunction')
     .asFunction();
 
 /// int32_t jsIsPromise(JSContext *ctx, JSValueConst *val)
@@ -635,7 +635,7 @@ final int Function(
             Int32 Function(
       Pointer,
       Pointer,
-    )>>("jsIsPromise")
+    )>>('jsIsPromise')
     .asFunction();
 
 /// int32_t jsIsArray(JSContext *ctx, JSValueConst *val)
@@ -648,7 +648,7 @@ final int Function(
             Int32 Function(
       Pointer,
       Pointer,
-    )>>("jsIsArray")
+    )>>('jsIsArray')
     .asFunction();
 
 /// JSValue *jsGetProperty(JSContext *ctx, JSValueConst *this_obj,
@@ -664,7 +664,7 @@ final Pointer Function(
       Pointer,
       Pointer,
       Uint32,
-    )>>("jsGetProperty")
+    )>>('jsGetProperty')
     .asFunction();
 
 /// int jsDefinePropertyValue(JSContext *ctx, JSValueConst *this_obj,
@@ -684,7 +684,7 @@ final int Function(
       Uint32,
       Pointer,
       Int32,
-    )>>("jsDefinePropertyValue")
+    )>>('jsDefinePropertyValue')
     .asFunction();
 
 /// void jsFreeAtom(JSContext *ctx, JSAtom v)
@@ -697,7 +697,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Uint32,
-    )>>("jsFreeAtom")
+    )>>('jsFreeAtom')
     .asFunction();
 
 /// JSAtom jsValueToAtom(JSContext *ctx, JSValueConst *val)
@@ -710,7 +710,7 @@ final int Function(
             Uint32 Function(
       Pointer,
       Pointer,
-    )>>("jsValueToAtom")
+    )>>('jsValueToAtom')
     .asFunction();
 
 /// JSValue *jsAtomToValue(JSContext *ctx, JSAtom val)
@@ -723,7 +723,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Uint32,
-    )>>("jsAtomToValue")
+    )>>('jsAtomToValue')
     .asFunction();
 
 /// int jsGetOwnPropertyNames(JSContext *ctx, JSPropertyEnum **ptab,
@@ -743,7 +743,7 @@ final int Function(
       Pointer<Uint32>,
       Pointer,
       Int32,
-    )>>("jsGetOwnPropertyNames")
+    )>>('jsGetOwnPropertyNames')
     .asFunction();
 
 /// JSAtom jsPropertyEnumGetAtom(JSPropertyEnum *ptab, int i)
@@ -756,12 +756,12 @@ final int Function(
             Uint32 Function(
       Pointer,
       Int32,
-    )>>("jsPropertyEnumGetAtom")
+    )>>('jsPropertyEnumGetAtom')
     .asFunction();
 
 /// uint32_t sizeOfJSValue()
 final int Function() _sizeOfJSValue = _qjsLib
-    .lookup<NativeFunction<Uint32 Function()>>("sizeOfJSValue")
+    .lookup<NativeFunction<Uint32 Function()>>('sizeOfJSValue')
     .asFunction();
 
 final sizeOfJSValue = _sizeOfJSValue();
@@ -778,7 +778,7 @@ final void Function(
       Pointer,
       Uint32,
       Pointer,
-    )>>("setJSValueList")
+    )>>('setJSValueList')
     .asFunction();
 
 /// JSValue *jsCall(JSContext *ctx, JSValueConst *func_obj, JSValueConst *this_obj,
@@ -798,7 +798,7 @@ final Pointer Function(
       Pointer,
       Int32,
       Pointer,
-    )>>("jsCall")
+    )>>('jsCall')
     .asFunction();
 
 Pointer jsCall(
@@ -834,7 +834,7 @@ final int Function(
         NativeFunction<
             Int32 Function(
       Pointer,
-    )>>("jsIsException")
+    )>>('jsIsException')
     .asFunction();
 
 /// JSValue *jsGetException(JSContext *ctx)
@@ -845,7 +845,7 @@ final Pointer Function(
         NativeFunction<
             Pointer Function(
       Pointer,
-    )>>("jsGetException")
+    )>>('jsGetException')
     .asFunction();
 
 /// int jsExecutePendingJob(JSRuntime *rt)
@@ -856,7 +856,7 @@ final int Function(
         NativeFunction<
             Int32 Function(
       Pointer,
-    )>>("jsExecutePendingJob")
+    )>>('jsExecutePendingJob')
     .asFunction();
 
 /// JSValue *jsNewPromiseCapability(JSContext *ctx, JSValue *resolving_funcs)
@@ -869,7 +869,7 @@ final Pointer Function(
             Pointer Function(
       Pointer,
       Pointer,
-    )>>("jsNewPromiseCapability")
+    )>>('jsNewPromiseCapability')
     .asFunction();
 
 /// void jsFree(JSContext *ctx, void *ptab)
@@ -882,5 +882,5 @@ final void Function(
             Void Function(
       Pointer,
       Pointer,
-    )>>("jsFree")
+    )>>('jsFree')
     .asFunction();
diff --git a/lib/flutter_qjs.dart b/lib/flutter_qjs.dart
index e02deb8..07f3db4 100644
--- a/lib/flutter_qjs.dart
+++ b/lib/flutter_qjs.dart
@@ -50,20 +50,25 @@ class FlutterQjs {
           case JSChannelType.METHON:
             final pdata = ptr.cast<Pointer>();
             final argc = pdata.elementAt(1).value.cast<Int32>().value;
-            List args = [];
+            List pargs = <Pointer>[];
             for (var i = 0; i < argc; i++) {
-              args.add(jsToDart(
-                  ctx,
-                  Pointer.fromAddress(
-                    pdata.elementAt(2).value.address + sizeOfJSValue * i,
-                  )));
+              pargs.add(Pointer.fromAddress(
+                pdata.elementAt(2).value.address + sizeOfJSValue * i,
+              ));
             }
-            final thisVal = jsToDart(ctx, pdata.elementAt(0).value);
+            final pThis = pdata.elementAt(0).value;
             JSInvokable func = jsToDart(ctx, pdata.elementAt(3).value);
-            final ret = func.invoke(args, thisVal);
-            return dartToJs(ctx, ret);
+            if (func is NativeJSInvokable) {
+              return dartToJs(ctx, func.invokeNative(ctx, pThis, pargs));
+            }
+            return dartToJs(
+                ctx,
+                func.invoke(
+                  pargs.map((e) => jsToDart(ctx, e)).toList(),
+                  jsToDart(ctx, pThis),
+                ));
           case JSChannelType.MODULE:
-            if (moduleHandler == null) throw Exception("No ModuleHandler");
+            if (moduleHandler == null) throw Exception('No ModuleHandler');
             var ret = Utf8.toUtf8(moduleHandler(
               Utf8.fromUtf8(ptr.cast<Utf8>()),
             ));
@@ -72,11 +77,11 @@ class FlutterQjs {
             });
             return ret;
           case JSChannelType.PROMISE_TRACK:
-            final errStr = parseJSException(ctx, perr: ptr);
+            final errStr = parseJSException(ctx, ptr);
             if (hostPromiseRejectionHandler != null) {
               hostPromiseRejectionHandler(errStr);
             } else {
-              print("unhandled promise rejection: $errStr");
+              print('unhandled promise rejection: $errStr');
             }
             return Pointer.fromAddress(0);
           case JSChannelType.FREE_OBJECT:
@@ -86,15 +91,15 @@ class FlutterQjs {
             runtimeOpaques[rt]?.ref?.remove(obj);
             return Pointer.fromAddress(0);
         }
-        throw Exception("call channel with wrong type");
+        throw Exception('call channel with wrong type');
       } catch (e, stack) {
-        final errStr = e.toString() + "\n" + stack.toString();
+        final errStr = e.toString() + '\n' + stack.toString();
         if (type == JSChannelType.FREE_OBJECT) {
-          print("DartObject release error: " + errStr);
+          print('DartObject release error: ' + errStr);
           return Pointer.fromAddress(0);
         }
         if (type == JSChannelType.MODULE) {
-          print("host Promise Rejection Handler error: " + errStr);
+          print('host Promise Rejection Handler error: ' + errStr);
           return Pointer.fromAddress(0);
         }
         var err = jsThrowInternalError(
@@ -143,12 +148,12 @@ class FlutterQjs {
     var jsval = jsEval(
       _ctx,
       command,
-      name ?? "<eval>",
+      name ?? '<eval>',
       evalFlags ?? JSEvalFlag.GLOBAL,
     );
     if (jsIsException(jsval) != 0) {
       jsFreeValue(_ctx, jsval);
-      throw Exception(parseJSException(_ctx));
+      throw parseJSException(_ctx);
     }
     var result = jsToDart(_ctx, jsval);
     jsFreeValue(_ctx, jsval);
diff --git a/lib/isolate.dart b/lib/isolate.dart
index 0180216..15dfc62 100644
--- a/lib/isolate.dart
+++ b/lib/isolate.dart
@@ -35,7 +35,7 @@ void _runJsIsolate(Map spawnMessage) async {
         'ptr': ptr.address,
       });
       while (ptr.value.address == 0) sleep(Duration.zero);
-      if (ptr.value.address == -1) throw Exception("Module Not found");
+      if (ptr.value.address == -1) throw Exception('Module Not found');
       var ret = Utf8.fromUtf8(ptr.value);
       sendPort.send({
         'type': 'release',
@@ -58,7 +58,7 @@ void _runJsIsolate(Map spawnMessage) async {
           );
           break;
         case 'call':
-          data = JSFunction.fromAddress(
+          data = await JSFunction.fromAddress(
             Pointer.fromAddress(msg['ctx']),
             Pointer.fromAddress(msg['val']),
           ).invoke(
@@ -79,7 +79,7 @@ void _runJsIsolate(Map spawnMessage) async {
     } catch (e, stack) {
       if (msgPort != null)
         msgPort.send({
-          'error': e.toString() + "\n" + stack.toString(),
+          'error': e.toString() + '\n' + stack.toString(),
         });
     }
   });
@@ -135,12 +135,12 @@ class IsolateQjs {
             if (hostPromiseRejectionHandler != null) {
               hostPromiseRejectionHandler(errStr);
             } else {
-              print("unhandled promise rejection: $errStr");
+              print('unhandled promise rejection: $errStr');
             }
           } catch (e, stack) {
-            print("host Promise Rejection Handler error: " +
+            print('host Promise Rejection Handler error: ' +
                 e.toString() +
-                "\n" +
+                '\n' +
                 stack.toString());
           }
           break;
diff --git a/lib/wrapper.dart b/lib/wrapper.dart
index 51563cb..fb4f52f 100644
--- a/lib/wrapper.dart
+++ b/lib/wrapper.dart
@@ -32,6 +32,20 @@ abstract class JSInvokable {
   }
 }
 
+class NativeJSInvokable extends JSInvokable {
+  dynamic Function(Pointer ctx, Pointer thisVal, List<Pointer> args) _func;
+  NativeJSInvokable(this._func);
+
+  @override
+  dynamic invoke(List args, [dynamic thisVal]) {
+    throw UnimplementedError('use invokeNative instead.');
+  }
+
+  invokeNative(Pointer ctx, Pointer thisVal, List<Pointer> args) {
+    _func(ctx, thisVal, args);
+  }
+}
+
 class _DartFunction extends JSInvokable {
   Function _func;
   _DartFunction(this._func);
@@ -40,7 +54,7 @@ class _DartFunction extends JSInvokable {
   invoke(List args, [thisVal]) {
     /// wrap this into function
     final passThis =
-        RegExp("{.*thisVal.*}").hasMatch(_func.runtimeType.toString());
+        RegExp('{.*thisVal.*}').hasMatch(_func.runtimeType.toString());
     return Function.apply(_func, args, passThis ? {#thisVal: thisVal} : null);
   }
 }
@@ -112,7 +126,7 @@ class JSFunction extends JSObject implements JSInvokable {
     bool isException = jsIsException(jsRet) != 0;
     if (isException) {
       jsFreeValue(_ctx, jsRet);
-      throw Exception(parseJSException(_ctx));
+      throw parseJSException(_ctx);
     }
     var ret = jsToDart(_ctx, jsRet);
     jsFreeValue(_ctx, jsRet);
@@ -180,7 +194,7 @@ class IsolateFunction extends JSInvokable implements DartReleasable {
     final JSInvokable invokable = JSInvokable.wrap(func);
     final funcPort = ReceivePort();
     funcPort.listen((msg) async {
-      if (msg == "close") return funcPort.close();
+      if (msg == 'close') return funcPort.close();
       var data;
       SendPort msgPort = msg['port'];
       try {
@@ -194,7 +208,7 @@ class IsolateFunction extends JSInvokable implements DartReleasable {
       } catch (e, stack) {
         if (msgPort != null)
           msgPort.send({
-            'error': e.toString() + "\n" + stack.toString(),
+            'error': e.toString() + '\n' + stack.toString(),
           });
       }
     });
@@ -221,7 +235,7 @@ class IsolateFunction extends JSInvokable implements DartReleasable {
   @override
   void release() {
     if (func == null) return;
-    func.send("close");
+    func.send('close');
     func = null;
   }
 }
@@ -275,7 +289,7 @@ dynamic encodeData(dynamic data, {Map<dynamic, dynamic> cache}) {
       futurePort.first.then((port) {
         futurePort.close();
         (port as SendPort)
-            .send({'error': e.toString() + "\n" + stack.toString()});
+            .send({'error': e.toString() + '\n' + stack.toString()});
       });
     });
     return {
@@ -344,12 +358,12 @@ dynamic decodeData(dynamic data, SendPort port, {Map<dynamic, dynamic> cache}) {
   return data;
 }
 
-String parseJSException(Pointer ctx, {Pointer perr}) {
+String parseJSException(Pointer ctx, [Pointer perr]) {
   final e = perr ?? jsGetException(ctx);
 
   var err = jsToCString(ctx, e);
   if (jsValueGetTag(e) == JSTag.OBJECT) {
-    Pointer stack = jsGetPropertyValue(ctx, e, "stack");
+    Pointer stack = jsGetPropertyValue(ctx, e, 'stack');
     if (jsToBool(ctx, stack) != 0) {
       err += '\n' + jsToCString(ctx, stack);
     }
@@ -409,7 +423,7 @@ Pointer dartToJs(Pointer ctx, dynamic val, {Map<dynamic, dynamic> cache}) {
     val.then((value) {
       res(value);
     }, onError: (e, stack) {
-      rej(e.toString() + "\n" + stack.toString());
+      rej(e.toString() + '\n' + stack.toString());
     });
     return ret;
   }
@@ -498,7 +512,7 @@ dynamic jsToDart(Pointer ctx, Pointer val, {Map<int, dynamic> cache}) {
       if (jsIsFunction(ctx, val) != 0) {
         return JSFunction(ctx, val);
       } else if (jsIsPromise(ctx, val) != 0) {
-        Pointer jsPromiseThen = jsGetPropertyValue(ctx, val, "then");
+        Pointer jsPromiseThen = jsGetPropertyValue(ctx, val, 'then');
         JSFunction promiseThen = jsToDart(ctx, jsPromiseThen, cache: cache);
         jsFreeValue(ctx, jsPromiseThen);
         var completer = Completer();
@@ -507,16 +521,18 @@ dynamic jsToDart(Pointer ctx, Pointer val, {Map<int, dynamic> cache}) {
           (v) {
             if (!completer.isCompleted) completer.complete(v);
           },
-          (e) {
-            if (!completer.isCompleted) completer.completeError(e);
-          },
+          NativeJSInvokable((ctx, thisVal, args) {
+            if (!completer.isCompleted)
+              completer
+                  .completeError(parseJSException(ctx, args[0]));
+          }),
         ], JSObject.fromAddress(ctx, val));
         bool isException = jsIsException(jsRet) != 0;
         jsFreeValue(ctx, jsRet);
-        if (isException) throw Exception(parseJSException(ctx));
+        if (isException) throw parseJSException(ctx);
         return completer.future;
       } else if (jsIsArray(ctx, val) != 0) {
-        Pointer jslength = jsGetPropertyValue(ctx, val, "length");
+        Pointer jslength = jsGetPropertyValue(ctx, val, 'length');
         int length = jsToInt64(ctx, jslength);
         List<dynamic> ret = [];
         cache[valptr] = ret;
diff --git a/pubspec.yaml b/pubspec.yaml
index 6c6deaa..c882ae1 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: flutter_qjs
 description: This plugin is a simple js engine for flutter using the `quickjs` project. Plugin currently supports all the platforms except web!
-version: 0.3.1
+version: 0.3.2
 homepage: https://github.com/ekibun/flutter_qjs
 
 environment:
diff --git a/test/flutter_qjs_test.dart b/test/flutter_qjs_test.dart
index 923a6a3..7438833 100644
--- a/test/flutter_qjs_test.dart
+++ b/test/flutter_qjs_test.dart
@@ -158,7 +158,7 @@ void main() async {
       qjs.evaluate("a=()=>a();a();", name: "<eval>");
     } catch (e) {
       expect(
-          e.toString(), startsWith('Exception: InternalError: stack overflow'),
+          e.toString(), startsWith('InternalError: stack overflow'),
           reason: "throw stack overflow");
     }
     qjs.close();