title: Getting keys of a class in typescript
body: <p>I have a class with a lot of methods let's call it myClass. I'm calling it like this:</p>
  
  <pre><code>myClass[key]()
  </code></pre>
  
  <p>Is there a way to get the possible values from key? I hoped for something like keyof myClass, but I got 'myClass refers to a value, but is being used as a type here'</p>
  
  <p>The problem is probably that as of now myClass is defined in a .js-file and encapsulated like this:</p>
  
  <pre><code>const myClass = new MyActualClass();
  export default myClass
  </code></pre>
  
  <p>Is it possible to extract the information without converting the .js file to typescript, and extract the information from MyActualClass directly?</p>