title: Access prototype from generic
body: <p>Is it possible for a class with a generic such as <code>class Foo&lt;A&gt; {}</code> to access <code>A</code>'s prototype or use a typeguard on <code>A</code>, or run any sort of logic based on <code>A</code>'s type alone - without having been provided the class, interface, or instance to <code>Foo</code>'s constructor (i.e. <code>Foo</code> has no constructor or the constructor does not accept an argument of type <code>A</code>)?</p>
  
  <p>There are several answers about accessing the constructor, such as <a href="https://stackoverflow.com/questions/24677592/generic-type-inference-with-class-argument?noredirect=1&amp;lq=1">Generic Type Inference with Class Argument</a> but I am only interested in running different logic based on the type, not instantiating a new instance of it.</p>
  
  <p>Specifically, I want to know if <code>A.prototype</code> has a certain method defined on it.</p>