title: Confirming Navigation with React Router without Mixin for es6 Classes
body: <p>With React Router is there a way to use confirm leaving a route without using a mixin? We are using es6 Classes and can't use a mixin.</p>
  
  <p>This is what I am trying to accomplish:
  <a href="https://github.com/rackt/react-router/blob/latest/docs/guides/advanced/ConfirmingNavigation.md" rel="nofollow">https://github.com/rackt/react-router/blob/latest/docs/guides/advanced/ConfirmingNavigation.md</a></p>