How to detect if a ScriptObject is a v8 Error?

[viceice]

I'm trying to implement a simple console and like to get more details when a Error object is passed.

When i run that in something like try { dotnetMethod(); } catch (e) { console.log(e); } and the dotnetMethod throws an Exception, then i only get the message when calling toString instead of a stack trace.

public class JsConsole
{
    public void log(params object[] args)
    {
        foreach (var arg in args)
        {
            if (arg is ScriptObject o)
            {
                // This only gives error message without stack when underlying exception comes from dotnet method call.
                Console.WriteLine(o.InvokeMethod("toString"));
            } else
            {
                Console.WriteLine(arg?.ToString());
            }
        }
    }
}

So what's the best way to detect if the o is an Error object?

[viceice]

A hacky way is this:

if ((o.GetProperty("constructor") as ScriptObject)?.PropertyNames.Contains("stackTraceLimit") == true)
{
    writer.Append(o.GetProperty("stack"));
} else
{
    writer.Append(o.InvokeMethod("toString"));
}

[ClearScriptLib]

Hi @viceice,

Why not let the script engine help? Consider:

dynamic isInstanceOf = engine.Evaluate("(x, y) => x instanceof y");

And then:

if (isInstanceOf(obj, engine.Script.Error)) {
    Console.WriteLine("The object is a JavaScript Error!");
}

Good luck!

[viceice]

thanks, too easy 🙈😄