How to create node.js error object in native addon?

Question

I want to create an error object. But there is no v8::Error::New() How can I create an error object?

    v8::Handle< v8::Value > result = v8::Undefined();
    v8::Handle< v8::Value > error = v8::Undefined();

    if(m_errorMsg.empty())
    {
        // Not error
    }
    else
    {
        // HERE: Instead of a string I want an error object.
        error = v8::String::New( m_errorMsg.c_str() );
    }

    v8::Handle< v8::Value > argv[] = { error, result };

    m_callback->Call(v8::Context::GetCurrent()->Global(), 2, argv);

Answer 1

actually the api was changed. now, you can throw an exception in this way

...
Isolate* isolate = args.GetIsolate();
isolate->ThrowException(Exception::TypeError(
    String::NewFromUtf8(isolate, "Your error message")));
...

Answer 2

This is not specific to Node, you can just use the ThrowException method from the V8 API. It requires one parameter of type Exception which you can create with one of the static methods on the Exception class.

There are examples on how to do it in this Node tutorial but feel free to check out my code on GitHub too.

ThrowException(Exception::TypeError(String::New("This is an error, oh yes.")));
return Undefined();

NOTE: Don't forget to return with Undefined() after calling ThrowException. (Even scope.close is unnecessary in this case.)

Further reading:

• documentation of the ThrowException method:
  http://bespin.cz/~ondras/html/namespacev8.html#a2469af0ac719d39f77f20cf68dd9200e
• documentation of the Exception class:
  http://bespin.cz/~ondras/html/classv8_1_1Exception.html