JavaScript ForEach Index Value!

[egooner]

I have a JavaScript forEach iterating over a Host Object which has a simple IEnumerable Implemented

    public IEnumerator<T> GetEnumerator()
    {
        foreach (String cfgKey in configbag.KeyList)
        {
            T t = (T)configbag[cfgKey];
            if (t == null)
            {
                yield return default(T);
            }
            else
            {
                yield return t;
            }
        }
    }

The JavaScript works fine if I issue a simple

bags.forEach((bag) =>{do something with bag})

But if I want the Index too

bags.forEach((bag,n) =>{do something with bag but use n also})

n is Undefined.

Not sure what I need to add or if this is even possible? Can you advise what I need to do in order to obtain the index of the enumerated item. Obviously I could roll this back to a simple for loop or add my own index but I am trying to make the code work in the same way as a Javascript array object.

[egooner]

Oops too much code thought forEach was implemented in V8 but it seems to be my own extension!!!

[egooner]

For anyone interested this is what the new forEach Extension I created looks like

public static class ScriptEnumerable
{
    public static void forEach<T>(this IEnumerable<T> source, object action)
    {
        int i = 0;        
        foreach (var item in source)
        {            
            ((dynamic)action)(item,i++,source);                       
        }        
    }
}

The original that I think I got from this forum when on CodePlex was

public static class ScriptEnumerable
{
    public static void forEach<T>(this IEnumerable<T> source, object action)
    {
        source.ToList().ForEach(item => ((dynamic)action)(item));
    }
}