popToRoute() not working when I pass in route object - navigator

Question

I've googled this a bunch and there aren't sufficient examples or explanations that tell me how popToRoute(), the react-native navigator method exactly works. Would be awesome if someone could help me better understand it.
I'm passing in my route object (which is definitely correct) but get the error: "Invariant Violation: Calling popToRoute for a route that doesn't exist!"
Here is the relevant code where I use the popToRoute() navigator method:
var InviteRoommates = React.createClass({
submitRoommates: function() {
this.props.navigator.popToRoute({
index: 3,
id: 'ItemList'
});
},
render: function() {
return (
<View style={styles.container}>
<Text>INVITE ROOMMATES</Text>
<TextInput style={styles.input} placeholder="roommate's email address"/>
<TouchableHighlight
style={styles.button}
onPress={() => this.submitRoommates()}
>
<Text style={styles.btnText}>Submit</Text>
</TouchableHighlight>
</View>
);
}
});

Answer 1

I wrote the exact same code as you, have the same problem. Found a solution that works, although ugly. Access all the route objects with this.props.navigator.getCurrentRouts(), then specifying one by it's index in the array. Of course this only works if you know the route object's position in the stack at all times....
this.props.navigator.popToRoute(this.props.navigator.getCurrentRoutes()[1]);

Answer 2

If you want to popToRoute by name you can simply loop through the route stack and check each route by name, then pop to that route.
var routes = this.props.navigator.state.routeStack;
for (var i = routes.length - 1; i >= 0; i--) {
if(routes[i].name === "MyDestinationRoute"){
var destinationRoute = this.props.navigator.getCurrentRoutes()[i]
this.props.navigator.popToRoute(destinationRoute);
}
}

Answer 3

This worked for me.
const routes = this.props.navigator.getCurrentRoutes();
const routeToGo = routes.find( route => route.name == 'the name of the route');
this.props.navigator.popToRoute(routeToGo);