Summary: 1. Add a new api `top` which returns the root navigator of a nested navigator.
2. Remove the param `context` from the method `addListener` because it's not used and not necessary.
public
Reviewed By: fkgozali
Differential Revision: D2613852
fb-gh-sync-id: 0d5544422ff0be7875824989a4fbefbef9aac986
Summary: Adds the API that enables the navigation events capturing and bubbling which is the feature
that is enabled if the nested navigation contexts is created by the navigator.
This would allow developer to observe or reconcile navigation events within the navigation tree.
public
./Libraries/FBReactKit/jest
Reviewed By: zjj010104
Differential Revision: D2546451
fb-gh-sync-id: dfc9d16defaa563b9e80fd751a20570f6e524b74
