With this, the user will be able to specify a `getId` function for their screens which returns an unique ID to use for the screen:
```js
<Stack.Screen
name="Profile"
component={ProfileScreen}
getId={({ params }) => params.userId}
/>
```
This is an alternative to the `key` option in `navigate` with several advantages:
- Often users specify a key that's dependent on data already in params, such as `userId`. So it's much easier to specify it one place rather than at every call site.
- Users won't need to deal with generating a unique key for routes manually.
- This will work with other actions such as `push`, and not just navigate.
- With this, it'll be possible to have multiple instances of the screen even if you use `navigate`, which may be desirable in many cases (such as profile screens).
This commit adds new `header` and `headerShown` options in drawer navigator to be able to show a header, along with a bunch of header related options similar to stack navigator.
Historically, we have suggested to nest a stack navigator inside drawer navigator to render a header. While it works, it's not efficient to nest an entire navigator just for a header, considering it adds a lot of additional overhead from the code to handle animations, gestures etc. which won't ever be run in this case. It also increases the view hierarchy which has negative impacts on performance on Android, and could cause content not to render on older iOS devices.
Another issue with the approach is that since drawer navigator is at the root in this setup, it's possible to open drawer from every screen in the stack navigator, which usually isn't the expected behaviour. It's necessary to write additional code to disable the gesture to open drawer in all screens but first.
In addition, users also need to add a custom drawer icon to the header manually to be able to toggle the drawer
If drawer navigator could render its own header we'd avoid all these shortcomings as well as make the code simpler.
For now, I have implemented a new `Header` component in drawer since it's way simpler than stack navigator header. Though we may consider creating a shared UI package and add such components there which all our navigators could use.
The `Header` includes a button to toggle the drawer by default, and supports customization options such as showing custom left/right/title components. For this commit, I have kept `headerShown` to `false` by default coz I wasn't sure if it'd be a breaking change to start showing headers in drawers. Probably we can toggle it to `true` by default in next major.
Previously, 'resetRoot' directly performed a 'setState' on the container instead of dispatching an action. This meant that hooks such as listener for 'preventRemove' won't be notified by it. This commit changes it to dispatch a regular 'RESET' action which will behave the same as other actions.
When navigating from ScreenA to ScreenB and then back to ScreenA,
react-navigation unconditionally calls `Keyboard.dismiss()`.
If the user is fast enough and taps on a `TextInput` after coming
back from ScreenB, the keyboard opens, just to be dismissed again.
This would also happen if some logic automatically focuses the
`TextInput` in ScreenA. This behaviour can be seen observed in
https://snack.expo.io/lTDZhVNhV.
