better error handling (#56)

* better errror handling

include/pyjs/pycpp/error_handling.py

@@ -13,6 +13,13 @@ def __init__(self, err, message=None):
         # default message
         if message is None:
             message = js.JSON.stringify(err, js.Object.getOwnPropertyNames(err))
+
+        self.name = "UnknownError"
+        try:
+            self.name = err.name
+        except  AttributeError:
+            pass
+
         self.message = message
 
         # i

src/export_js_proxy.cpp

@@ -80,6 +80,21 @@ namespace pyjs
         {
             std::stringstream ss;
             ss << "has no attribute/key ";
+
+            // check if key is a string
+            if (key->typeOf().as<std::string>() == "string")
+            {
+                ss << key->as<std::string>();
+            }
+            else if (key->typeOf().as<std::string>() == "number")
+            {
+                ss << key->as<int>();
+            }
+            else
+            {
+                ss << "[unknown key type]";
+            }
+
             throw pybind11::attribute_error(ss.str());
         }
         return implicit_js_to_py(wrapped_return_value["ret"], type_string);