title: JS Generators: How is `return yield` different from `yield`?
body: <pre><code>function* foo() {
    yield 123
  };
  
  // - - -
  
  function* foo() {
    return yield 123
  };
  </code></pre>
  
  <p>I can’t seem to demonstrate the difference between the two.</p>
  
  <ul>
  <li>Is there a demonstrable difference?</li>
  <li>Should <code>return</code> be used in a generator?</li>
  </ul>