Double tap on Narrow narrows twice.

[roberthoenig]

Issue

It's not visible, but I rapidly tapped twice on the same topic.
This was recorded on an iOS device. I experience the same behavior in an Android emulator.
There is a issue for this: react-navigation/rfcs#16
The developers seem unsure whether this is a bug or a feature, but they point to some ways to resolve this manually.

Possible solution

File: src/nav/navReducers.js
39: const switchNarrow = (state: NavigationState, action: SwitchNarrowAction): NavigationState => {
40:   if (state.isTransitioning === false) {
41:     return AppNavigator.router.getStateForAction(navigateToChat(action.narrow), state) || state;
42:   }
43:   return state;
44: }

This drops any transitions dispatched while the app is transitioning. This does its job, but I think an ideal solution would avoid narrowing to a view the app is already in alltogether.
Such a solution would require smt like this:

File: src/nav/navActions.js
11: export const navigateToChat = (narrow: Narrow): NavigateAction =>
12:     NavigationActions.navigate({ key: narrow, routeName: 'chat', params: { narrow } }); 

This makes the app throw when navigating to a chat narrow that has the same key as the narrow the app is in. (Currently, it just navigates twice.) We might want to do this for every narrow, and/or implement a check somewhere to not execute a narrow to the same view. I'm not sure what the philosophical right way to do this is.

[roberthoenig]

Stepping back, I think there are two questions here:

• What do we want to do when a narrow action is dispatched while another narrow is going on?

• What do we want to do when a narrow action is dispatched that narrows to the same narrow we are currently in?