diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2a2e57..b1698fb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 ## 0.3.2
 
 * fix Promise reject cannot get Exception string.
+* wrap JSError.
 
 ## 0.3.1
 
diff --git a/README.md b/README.md
index 2a85e43..ed6a242 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,7 @@ Data conversion between dart and js are implemented as follow:
 | Map                     | Object             |
 | Function<br>JSInvokable | function(....args) |
 | Future                  | Promise            |
+| JSError                 | Error              |
 | Object                  | DartObject         |
 
 **notice:** `JSInvokable` does not extend `Function`, but can be used same as `Function`.
diff --git a/cxx/ffi.cpp b/cxx/ffi.cpp
index 1402678..3e799da 100644
--- a/cxx/ffi.cpp
+++ b/cxx/ffi.cpp
@@ -13,9 +13,9 @@
 extern "C"
 {
 
-  DLLEXPORT JSValue *jsThrowInternalError(JSContext *ctx, char *message)
+  DLLEXPORT JSValue *jsThrow(JSContext *ctx, JSValue *obj)
   {
-    return new JSValue(JS_ThrowInternalError(ctx, "%s", message));
+    return new JSValue(JS_Throw(ctx, *obj));
   }
 
   DLLEXPORT JSValue *jsEXCEPTION()
@@ -293,6 +293,16 @@ extern "C"
     return JS_IsArray(ctx, *val);
   }
 
+  DLLEXPORT int32_t jsIsError(JSContext *ctx, JSValueConst *val)
+  {
+    return JS_IsError(ctx, *val);
+  }
+
+  DLLEXPORT JSValue *jsNewError(JSContext *ctx)
+  {
+    return new JSValue(JS_NewError(ctx));
+  }
+
   DLLEXPORT JSValue *jsGetProperty(JSContext *ctx, JSValueConst *this_obj,
                                    JSAtom prop)
   {
diff --git a/cxx/ffi.h b/cxx/ffi.h
index a1ca636..66fddb3 100644
--- a/cxx/ffi.h
+++ b/cxx/ffi.h
@@ -17,7 +17,7 @@ extern "C"
 
   typedef void *JSChannel(JSContext *ctx, size_t type, void *argv);
 
-  DLLEXPORT JSValue *jsThrowInternalError(JSContext *ctx, char *message);
+  DLLEXPORT JSValue *jsThrow(JSContext *ctx, JSValue *obj);
 
   DLLEXPORT JSValue *jsEXCEPTION();
 
@@ -95,6 +95,10 @@ extern "C"
 
   DLLEXPORT int32_t jsIsArray(JSContext *ctx, JSValueConst *val);
 
+  DLLEXPORT int32_t jsIsError(JSContext *ctx, JSValueConst *val);
+
+  DLLEXPORT JSValue *jsNewError(JSContext *ctx);
+
   DLLEXPORT JSValue *jsGetProperty(JSContext *ctx, JSValueConst *this_obj,
                                    JSAtom prop);
 
diff --git a/lib/ffi.dart b/lib/ffi.dart
index 4a07bd5..44e34c0 100644
--- a/lib/ffi.dart
+++ b/lib/ffi.dart
@@ -67,26 +67,19 @@ final DynamicLibrary _qjsLib = Platform.environment['FLUTTER_TEST'] == 'true'
             ? DynamicLibrary.open('libqjs.so')
             : DynamicLibrary.process());
 
-/// JSValue *jsThrowInternalError(JSContext *ctx, char *message)
+/// DLLEXPORT JSValue *jsThrow(JSContext *ctx, JSValue *obj)
 final Pointer Function(
   Pointer ctx,
-  Pointer<Utf8> message,
-) _jsThrowInternalError = _qjsLib
+  Pointer obj,
+) jsThrow = _qjsLib
     .lookup<
         NativeFunction<
             Pointer Function(
       Pointer,
-      Pointer<Utf8>,
-    )>>('jsThrowInternalError')
+      Pointer,
+    )>>('jsThrow')
     .asFunction();
 
-Pointer jsThrowInternalError(Pointer ctx, String message) {
-  var utf8message = Utf8.toUtf8(message);
-  var val = _jsThrowInternalError(ctx, utf8message);
-  free(utf8message);
-  return val;
-}
-
 /// JSValue *jsEXCEPTION()
 final Pointer Function() jsEXCEPTION = _qjsLib
     .lookup<NativeFunction<Pointer Function()>>('jsEXCEPTION')
@@ -117,6 +110,7 @@ class RuntimeOpaque {
   List<JSRef> ref = [];
   ReceivePort port;
   int dartObjectClassId;
+  int jsExceptionClassId;
 }
 
 final Map<Pointer, RuntimeOpaque> runtimeOpaques = Map();
@@ -164,10 +158,11 @@ final void Function(
 void jsFreeRuntime(
   Pointer rt,
 ) {
-  runtimeOpaques[rt]?.ref?.forEach((val) {
-    val.release();
-  });
-  runtimeOpaques.remove(rt);
+  while (0 < runtimeOpaques[rt]?.ref?.length ?? 0) {
+    final ref = runtimeOpaques[rt]?.ref?.first;
+    ref.release();
+    runtimeOpaques[rt]?.ref?.remove(ref);
+  }
   _jsFreeRuntime(rt);
 }
 
@@ -200,6 +195,7 @@ Pointer jsNewContext(Pointer rt) {
   final runtimeOpaque = runtimeOpaques[rt];
   if (runtimeOpaque == null) throw Exception('Runtime has been released!');
   runtimeOpaque.dartObjectClassId = jsNewClass(ctx, 'DartObject');
+  runtimeOpaque.jsExceptionClassId = jsNewClass(ctx, 'JSException');
   return ctx;
 }
 
@@ -651,6 +647,30 @@ final int Function(
     )>>('jsIsArray')
     .asFunction();
 
+/// DLLEXPORT int32_t jsIsError(JSContext *ctx, JSValueConst *val);
+final int Function(
+  Pointer ctx,
+  Pointer val,
+) jsIsError = _qjsLib
+    .lookup<
+        NativeFunction<
+            Int32 Function(
+      Pointer,
+      Pointer,
+    )>>('jsIsError')
+    .asFunction();
+
+/// DLLEXPORT JSValue *jsNewError(JSContext *ctx);
+final Pointer Function(
+  Pointer ctx,
+) jsNewError = _qjsLib
+    .lookup<
+        NativeFunction<
+            Pointer Function(
+      Pointer,
+    )>>('jsNewError')
+    .asFunction();
+
 /// JSValue *jsGetProperty(JSContext *ctx, JSValueConst *this_obj,
 ///                           JSAtom prop)
 final Pointer Function(
diff --git a/lib/flutter_qjs.dart b/lib/flutter_qjs.dart
index 07f3db4..cb2513b 100644
--- a/lib/flutter_qjs.dart
+++ b/lib/flutter_qjs.dart
@@ -50,25 +50,24 @@ class FlutterQjs {
           case JSChannelType.METHON:
             final pdata = ptr.cast<Pointer>();
             final argc = pdata.elementAt(1).value.cast<Int32>().value;
-            List pargs = <Pointer>[];
+            List pargs = [];
             for (var i = 0; i < argc; i++) {
-              pargs.add(Pointer.fromAddress(
-                pdata.elementAt(2).value.address + sizeOfJSValue * i,
+              pargs.add(jsToDart(
+                ctx,
+                Pointer.fromAddress(
+                  pdata.elementAt(2).value.address + sizeOfJSValue * i,
+                ),
               ));
             }
-            final pThis = pdata.elementAt(0).value;
             JSInvokable func = jsToDart(ctx, pdata.elementAt(3).value);
-            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),
+                  pargs,
+                  jsToDart(ctx, pdata.elementAt(0).value),
                 ));
           case JSChannelType.MODULE:
-            if (moduleHandler == null) throw Exception('No ModuleHandler');
+            if (moduleHandler == null) throw JSError('No ModuleHandler');
             var ret = Utf8.toUtf8(moduleHandler(
               Utf8.fromUtf8(ptr.cast<Utf8>()),
             ));
@@ -79,7 +78,7 @@ class FlutterQjs {
           case JSChannelType.PROMISE_TRACK:
             final errStr = parseJSException(ctx, ptr);
             if (hostPromiseRejectionHandler != null) {
-              hostPromiseRejectionHandler(errStr);
+              hostPromiseRejectionHandler(errStr.toString());
             } else {
               print('unhandled promise rejection: $errStr');
             }
@@ -91,21 +90,19 @@ class FlutterQjs {
             runtimeOpaques[rt]?.ref?.remove(obj);
             return Pointer.fromAddress(0);
         }
-        throw Exception('call channel with wrong type');
-      } catch (e, stack) {
-        final errStr = e.toString() + '\n' + stack.toString();
+        throw JSError('call channel with wrong type');
+      } catch (e) {
         if (type == JSChannelType.FREE_OBJECT) {
-          print('DartObject release error: ' + errStr);
+          print('DartObject release error: $e');
           return Pointer.fromAddress(0);
         }
         if (type == JSChannelType.MODULE) {
-          print('host Promise Rejection Handler error: ' + errStr);
+          print('host Promise Rejection Handler error: $e');
           return Pointer.fromAddress(0);
         }
-        var err = jsThrowInternalError(
-          ctx,
-          errStr,
-        );
+        var throwObj = dartToJs(ctx, e);
+        var err = jsThrow(ctx, throwObj);
+        jsFreeValue(ctx, throwObj);
         if (type == JSChannelType.MODULE) {
           jsFreeValue(ctx, err);
           return Pointer.fromAddress(0);
diff --git a/lib/isolate.dart b/lib/isolate.dart
index 15dfc62..5f481dc 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 JSError('Module Not found');
       var ret = Utf8.fromUtf8(ptr.value);
       sendPort.send({
         'type': 'release',
@@ -76,10 +76,10 @@ void _runJsIsolate(Map spawnMessage) async {
         msgPort.send({
           'data': encodeData(data),
         });
-    } catch (e, stack) {
+    } catch (e) {
       if (msgPort != null)
         msgPort.send({
-          'error': e.toString() + '\n' + stack.toString(),
+          'error': encodeData(e),
         });
     }
   });
@@ -137,11 +137,8 @@ class IsolateQjs {
             } else {
               print('unhandled promise rejection: $errStr');
             }
-          } catch (e, stack) {
-            print('host Promise Rejection Handler error: ' +
-                e.toString() +
-                '\n' +
-                stack.toString());
+          } catch (e) {
+            print('host Promise Rejection Handler error: $e');
           }
           break;
         case 'module':
@@ -197,6 +194,6 @@ class IsolateQjs {
     if (result.containsKey('data')) {
       return decodeData(result['data'], sendPort);
     } else
-      throw result['error'];
+      throw decodeData(result['error'], sendPort);
   }
 }
diff --git a/lib/wrapper.dart b/lib/wrapper.dart
index fb4f52f..b172962 100644
--- a/lib/wrapper.dart
+++ b/lib/wrapper.dart
@@ -12,6 +12,37 @@ import 'dart:typed_data';
 import 'package:ffi/ffi.dart';
 import 'ffi.dart';
 
+class JSError {
+  String message;
+  String stack;
+  JSError(message, [stack]) {
+    if (message is JSError) {
+      this.message = message.message;
+      this.stack = message.stack;
+    } else {
+      this.message = message.toString();
+      this.stack = (stack ?? StackTrace.current).toString();
+    }
+  }
+  @override
+  String toString() {
+    return stack == null ? message.toString() : "$message\n$stack";
+  }
+
+  static JSError decode(Map obj) {
+    if (obj.containsKey('__js_error'))
+      return JSError(obj['__js_error'], obj['__js_error_stack']);
+    return null;
+  }
+
+  Map encode() {
+    return {
+      '__js_error': message,
+      '__js_error_stack': stack,
+    };
+  }
+}
+
 abstract class JSInvokable {
   dynamic invoke(List args, [dynamic thisVal]);
 
@@ -32,19 +63,19 @@ abstract class JSInvokable {
   }
 }
 
-class NativeJSInvokable extends JSInvokable {
-  dynamic Function(Pointer ctx, Pointer thisVal, List<Pointer> args) _func;
-  NativeJSInvokable(this._func);
+// 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.');
-  }
+//   @override
+//   dynamic invoke(List args, [dynamic thisVal]) {
+//     throw UnimplementedError('use invokeNative instead.');
+//   }
 
-  invokeNative(Pointer ctx, Pointer thisVal, List<Pointer> args) {
-    _func(ctx, thisVal, args);
-  }
-}
+//   invokeNative(Pointer ctx, Pointer thisVal, List<Pointer> args) {
+//     _func(ctx, thisVal, args);
+//   }
+// }
 
 class _DartFunction extends JSInvokable {
   Function _func;
@@ -181,7 +212,7 @@ class IsolateJSFunction extends JSInvokable {
     if (result.containsKey('data'))
       return decodeData(result['data'], port);
     else
-      throw result['error'];
+      throw decodeData(result['error'], port);
   }
 }
 
@@ -205,10 +236,10 @@ class IsolateFunction extends JSInvokable implements DartReleasable {
           msgPort.send({
             'data': encodeData(data),
           });
-      } catch (e, stack) {
+      } catch (e) {
         if (msgPort != null)
           msgPort.send({
-            'error': e.toString() + '\n' + stack.toString(),
+            'error': encodeData(e),
           });
       }
     });
@@ -229,7 +260,7 @@ class IsolateFunction extends JSInvokable implements DartReleasable {
     if (result.containsKey('data'))
       return decodeData(result['data'], _port);
     else
-      throw result['error'];
+      throw decodeData(result['error'], _port);
   }
 
   @override
@@ -242,6 +273,7 @@ class IsolateFunction extends JSInvokable implements DartReleasable {
 
 dynamic encodeData(dynamic data, {Map<dynamic, dynamic> cache}) {
   if (cache == null) cache = Map();
+  if (data is JSError) return data.encode();
   if (cache.containsKey(data)) return cache[data];
   if (data is List) {
     var ret = [];
@@ -285,11 +317,10 @@ dynamic encodeData(dynamic data, {Map<dynamic, dynamic> cache}) {
         futurePort.close();
         (port as SendPort).send({'data': encodeData(value)});
       });
-    }, onError: (e, stack) {
+    }, onError: (e) {
       futurePort.first.then((port) {
         futurePort.close();
-        (port as SendPort)
-            .send({'error': e.toString() + '\n' + stack.toString()});
+        (port as SendPort).send({'error': encodeData(e)});
       });
     });
     return {
@@ -311,6 +342,8 @@ dynamic decodeData(dynamic data, SendPort port, {Map<dynamic, dynamic> cache}) {
     return ret;
   }
   if (data is Map) {
+    final jsException = JSError.decode(data);
+    if (jsException != null) return jsException;
     if (data.containsKey('__js_obj_val')) {
       int ctx = data['__js_obj_ctx'];
       int val = data['__js_obj_val'];
@@ -340,9 +373,9 @@ dynamic decodeData(dynamic data, SendPort port, {Map<dynamic, dynamic> cache}) {
       futurePort.first.then((value) {
         futurePort.close();
         if (value['error'] != null) {
-          futureCompleter.completeError(value['error']);
+          futureCompleter.completeError(decodeData(value['error'], port));
         } else {
-          futureCompleter.complete(value['data']);
+          futureCompleter.complete(decodeData(value['data'], port));
         }
       });
       return futureCompleter.future;
@@ -358,16 +391,13 @@ dynamic decodeData(dynamic data, SendPort port, {Map<dynamic, dynamic> cache}) {
   return data;
 }
 
-String parseJSException(Pointer ctx, [Pointer perr]) {
+dynamic 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');
-    if (jsToBool(ctx, stack) != 0) {
-      err += '\n' + jsToCString(ctx, stack);
-    }
-    jsFreeValue(ctx, stack);
+  var err;
+  try {
+    err = jsToDart(ctx, e);
+  } catch (exception) {
+    err = exception;
   }
   if (perr == null) jsFreeValue(ctx, e);
   return err;
@@ -409,6 +439,13 @@ Pointer jsGetPropertyValue(
 
 Pointer dartToJs(Pointer ctx, dynamic val, {Map<dynamic, dynamic> cache}) {
   if (val == null) return jsUNDEFINED();
+  if (val is JSError) {
+    final ret = jsNewError(ctx);
+    definePropertyValue(ctx, ret, "name", "");
+    definePropertyValue(ctx, ret, "message", val.message);
+    definePropertyValue(ctx, ret, "stack", val.stack);
+    return ret;
+  }
   if (val is JSObject) return jsDupValue(ctx, val._val);
   if (val is Future) {
     var resolvingFunc = allocate<Uint8>(count: sizeOfJSValue * 2);
@@ -422,8 +459,8 @@ Pointer dartToJs(Pointer ctx, dynamic val, {Map<dynamic, dynamic> cache}) {
     free(resolvingFunc);
     val.then((value) {
       res(value);
-    }, onError: (e, stack) {
-      rej(e.toString() + '\n' + stack.toString());
+    }, onError: (e) {
+      rej(e);
     });
     return ret;
   }
@@ -511,6 +548,15 @@ dynamic jsToDart(Pointer ctx, Pointer val, {Map<int, dynamic> cache}) {
       }
       if (jsIsFunction(ctx, val) != 0) {
         return JSFunction(ctx, val);
+      } else if (jsIsError(ctx, val) != 0) {
+        final err = jsToCString(ctx, val);
+        final pstack = jsGetPropertyValue(ctx, val, 'stack');
+        var stack;
+        if (jsToBool(ctx, pstack) != 0) {
+          stack = jsToCString(ctx, pstack);
+        }
+        jsFreeValue(ctx, pstack);
+        return JSError(err, stack);
       } else if (jsIsPromise(ctx, val) != 0) {
         Pointer jsPromiseThen = jsGetPropertyValue(ctx, val, 'then');
         JSFunction promiseThen = jsToDart(ctx, jsPromiseThen, cache: cache);
@@ -521,11 +567,9 @@ dynamic jsToDart(Pointer ctx, Pointer val, {Map<int, dynamic> cache}) {
           (v) {
             if (!completer.isCompleted) completer.complete(v);
           },
-          NativeJSInvokable((ctx, thisVal, args) {
-            if (!completer.isCompleted)
-              completer
-                  .completeError(parseJSException(ctx, args[0]));
-          }),
+          (e) {
+            if (!completer.isCompleted) completer.completeError(e);
+          },
         ], JSObject.fromAddress(ctx, val));
         bool isException = jsIsException(jsRet) != 0;
         jsFreeValue(ctx, jsRet);
diff --git a/test/flutter_qjs_test.dart b/test/flutter_qjs_test.dart
index 7438833..15580a3 100644
--- a/test/flutter_qjs_test.dart
+++ b/test/flutter_qjs_test.dart
@@ -12,6 +12,7 @@ import 'dart:io';
 import 'package:flutter_qjs/flutter_qjs.dart';
 import 'package:flutter_qjs/isolate.dart';
 import 'package:flutter_qjs/ffi.dart';
+import 'package:flutter_qjs/wrapper.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 dynamic myFunction(String args, {thisVal}) {
@@ -30,6 +31,10 @@ Future testEvaluate(qjs) async {
   for (var i = 0; i < primities.length; i++) {
     expect(wrapPrimities[i], primities[i], reason: "wrap primities");
   }
+  final jsError = JSError("test Error");
+  final wrapJsError = await testWrap(jsError);
+  expect(jsError.message, (wrapJsError as JSError).message,
+      reason: "wrap JSError");
   final wrapFunction = await testWrap(testWrap);
   final testEqual = await qjs.evaluate(
     "(a, b) => a === b",
@@ -60,8 +65,7 @@ Future testEvaluate(qjs) async {
     await promises[0];
     throw 'Future not reject';
   } catch (e) {
-    expect(e, startsWith('test Promise.reject\n'),
-        reason: "promise object reject");
+    expect(e, 'test Promise.reject', reason: "promise object reject");
   }
   expect(await promises[1], 'test Promise.resolve',
       reason: "promise object resolve");
@@ -156,9 +160,8 @@ void main() async {
     final qjs = FlutterQjs();
     try {
       qjs.evaluate("a=()=>a();a();", name: "<eval>");
-    } catch (e) {
-      expect(
-          e.toString(), startsWith('InternalError: stack overflow'),
+    } on JSError catch (e) {
+      expect(e.message, 'InternalError: stack overflow',
           reason: "throw stack overflow");
     }
     qjs.close();