2 files changed, 36 insertions, 7 deletions

diff --git a/src/binding.cc b/src/binding.cc
index cd8c67ef5..d8de138c1 100644
--- a/src/binding.cc
+++ b/src/binding.cc
@@ -47,20 +47,23 @@ static inline v8::Local<v8::String> v8_str(const char* x) {
 void HandleException(v8::Local<v8::Context> context,
                      v8::Local<v8::Value> exception) {
   auto* isolate = context->GetIsolate();
+  Deno* d = static_cast<Deno*>(isolate->GetData(0));
   v8::HandleScope handle_scope(isolate);
   v8::Context::Scope context_scope(context);
 
   auto message = v8::Exception::CreateMessage(isolate, exception);
   auto onerrorStr = v8::String::NewFromUtf8(isolate, "onerror");
   auto onerror = context->Global()->Get(onerrorStr);
+  auto stack_trace = message->GetStackTrace();
+  auto line =
+      v8::Integer::New(isolate, message->GetLineNumber(context).FromJust());
+  auto column =
+      v8::Integer::New(isolate, message->GetStartColumn(context).FromJust());
 
   if (onerror->IsFunction()) {
+    // window.onerror is set so we try to handle the exception in javascript.
     auto func = v8::Local<v8::Function>::Cast(onerror);
     v8::Local<v8::Value> args[5];
-    auto line =
-        v8::Integer::New(isolate, message->GetLineNumber(context).FromJust());
-    auto column =
-        v8::Integer::New(isolate, message->GetStartColumn(context).FromJust());
     args[0] = exception->ToString();
     args[1] = message->GetScriptResourceName();
     args[2] = line;
@@ -68,10 +71,36 @@ void HandleException(v8::Local<v8::Context> context,
     args[4] = exception;
     func->Call(context->Global(), 5, args);
     /* message, source, lineno, colno, error */
+  } else if (!stack_trace.IsEmpty()) {
+    // No javascript onerror handler, but we do have a stack trace. Format it
+    // into a string and add to last_exception.
+    std::string msg;
+    v8::String::Utf8Value exceptionStr(isolate, exception);
+    msg += ToCString(exceptionStr);
+    msg += "\n";
+
+    for (int i = 0; i < stack_trace->GetFrameCount(); ++i) {
+      auto frame = stack_trace->GetFrame(i);
+      v8::String::Utf8Value script_name(isolate, frame->GetScriptName());
+      int l = frame->GetLineNumber();
+      int c = frame->GetColumn();
+      char buf[512];
+      snprintf(buf, sizeof(buf), "%s %d:%d\n", ToCString(script_name), l, c);
+      msg += buf;
+    }
+    d->last_exception = msg;
   } else {
+    // No javascript onerror handler, no stack trace. Format the little info we
+    // have into a string and add to last_exception.
     v8::String::Utf8Value exceptionStr(isolate, exception);
-    printf("Unhandled Exception %s\n", ToCString(exceptionStr));
-    message->PrintCurrentStackTrace(isolate, stdout);
+    v8::String::Utf8Value script_name(isolate,
+                                      message->GetScriptResourceName());
+    v8::String::Utf8Value line_str(isolate, line);
+    v8::String::Utf8Value col_str(isolate, column);
+    char buf[512];
+    snprintf(buf, sizeof(buf), "%s\n%s %s:%s\n", ToCString(exceptionStr),
+             ToCString(script_name), ToCString(line_str), ToCString(col_str));
+    d->last_exception = std::string(buf);
   }
 }
 
diff --git a/src/main.cc b/src/main.cc
index 1f3b4cad8..0a6d76d34 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -57,7 +57,7 @@ int main(int argc, char** argv) {
   Deno* d = deno_new(NULL, MessagesFromJS);
   bool r = deno_execute(d, "deno_main.js", "denoMain();");
   if (!r) {
-    printf("Error! %s\n", deno_last_exception(d));
+    printf("%s\n", deno_last_exception(d));
     exit(1);
   }
   deno_delete(d);