How to know if route exists before i do transition

I want re-transition my application when route not found, in my application route

export default Ember.Route.extend({
  redirect: function(model, transition) {
    if (transition.targetName == "not-found") {
      var newPath = transition.intent.url  //do some logic
      this.transitionTo(newpath);
    }
  }
});

Question How to check if newPath exist before I do this.transitionTo(newPath);

In API I found only private hasRoute