Generate javascript from C# classes which inherit base class

Generate javascript from C# classes which inherit base class

I want to create a js file with a T4 template. The js file should reflect
all classes that inherit a specific base class. So it should pick up,
public SaveContactCommand : Commaand
{
}
But also
public SaveCustomerCommand : SaveContactCommand
{
}
Problem is since its done at design time I cant use regular code that
searches an assmeblie to get all C# classes. Are there any existing helper
library that I can use do get this working?