Documentation for blocking navigation actions like back

[brentvatne]

https://reactnavigation.org/docs/en/routers.html#blocking-navigation-actions - this is pretty barebones. One use case that came up was to fire a query when the user presses back and only complete that when the query is complete and the result matches some criteria. These docs don't say how to handle async

[jarvisluong]

Do you have any suggestions in mind to handle async? I looked at the source code of getStateForAction and it is not async itself so how do we get the router to wait until the async operation is completed?

[vdlindenmark]

For the back case: what I do is returning nothing and let my function handle the goBack action itself.