Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47473
For example,
```
declare function C<T>(ref: React.RefSetter<Set<T>>): React.Node;
type T = React.ElementRef<typeof C>
```
Previously Flow will evaluate `T` to `Set<mixed>`, by automatically replacing generic types with their upper bounds. But in the future it might be replaced with `empty`.
This diff cleans up instances like this in react-native codebase.
Changelog: [Internal]
Reviewed By: alexmckenley
Differential Revision: D65562571
fbshipit-source-id: bca2f4f022a5a23a5aa40886f5661899cb315f2e
Summary:
This pr is part of issue https://github.com/facebook/react-native/issues/46757 solving a task - [ME2E0008] [ME2E0009]
- Set up a test
- Starts the app
- Scrolls until flatlist is visilbe and clicks on flatlist
- Click basic button
- Scroll down until item 600 is visible
## Changelog:
[Internal] [Added] - Add e2e-test logic that click button & scroll down until specific item is visible
Pull Request resolved: https://github.com/facebook/react-native/pull/46804
Test Plan:
### Test Locally
- iOS
```bash
yarn install
cd packages/rn-tester
yarn e2e-build-ios
```
- Android
```bash
yarn install
cd packages/rn-tester
yarn e2e-build-android
```
### Start Maestro
- iOS
```bash
cd packages/rn-tester
yarn e2e-test-ios
```
- Android
```
cd packages/rn-tester
yarn e2e-test-android
```
### Test in CI
To test in CI, just add a comment on your PR with the text:
```
/test-e2e
```
Reviewed By: cortinico
Differential Revision: D63829274
Pulled By: cipolleschi
fbshipit-source-id: f7b4342ed353a48123f87dcfd8d503009f65637c
Summary:
During testing for 0.76-RC6, I came across the following behavior in RNTester.
Components > FlatList > Basic > Toggle `Empty` switch
You'll notice there are activity indicators in the header/footer (see video) for some time and things appear to be somewhat janky. I think the expectations would be to see only the `ListEmptyComponent` that is defined for this to look more correct. This will help not give any false indication that something has gone wrong with the latest picks when testing newer versions.
## Changelog:
[INTERNAL] [FIXED] - Fixed FlatList Empty behavior in RNTester
Pull Request resolved: https://github.com/facebook/react-native/pull/47094
Test Plan: https://github.com/user-attachments/assets/6e116641-5b24-473c-a654-7d32a081b83f
Reviewed By: yungsters
Differential Revision: D64541905
Pulled By: cipolleschi
fbshipit-source-id: 0447d99588d85f9e1a46c6da169a0838e94994bc
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38739
1. The separator here adds horizontal width, except when the cell is tapped. This is meant to be a visual effect for vertical FlatList, but makes `getItemLayout` incorrect and results in odd layout shifts. Do not use when horizontal.
2. Disabling "fixed height" leads to a barrage of errors because the example sets `initialScrollIndex` but does not set an `onScrollToIndexFailed` prop.
Changelog: [Internal]
Reviewed By: rozele
Differential Revision: D47978628
fbshipit-source-id: eb022c01bfd7df44c2f11d03ccc4580270c36a65
Summary:
`maintainVisibleContentPosition` is broken when using virtualization and the new content pushes visible content outside its "window". This can be reproduced in the example from this diff. When using a large page size it will always push visible content outside of the list "window" which will cause currently visible views to be unmounted so the implementation of `maintainVisibleContentPosition` can't adjust the content inset since the visible views no longer exist.
The first illustration shows the working case, when the new content doesn't push visible content outside the window. The red box represents the window, all views outside the box are not mounted, which means the native implementation of `maintainVisibleContentPosition` has no way to know it exists. In that case the first visible view is https://github.com/facebook/react-native/issues/2, after new content is added https://github.com/facebook/react-native/issues/2 is still inside the window so there's not problem adjusting content offset to maintain position. As you can see Step 1 and 3 result in the same position for all initial views.
The second illustation shows the broken case, when new content is added and pushes the first visible view outside the window. As you can see in step 2 the view https://github.com/facebook/react-native/issues/2 is no longer rendered so there's no way to maintain its position.
#### Illustration 1
#### Illustration 2
To fix `maintainVisibleContentPosition` when using `VirtualizedList` we need to make sure the visible items stay rendered when new items are added at the start of the list.
In order to do that we need to do the following:
- Detect new items that will cause content to be adjusted
- Add cells to render mask so that previously visible cells stay rendered
- Ignore certain updates while scroll metrics are invalid
### Detect new items that will cause content to be adjusted
The goal here is to know that scroll position will be updated natively by the `maintainVisibleContentPosition` implementation. The problem is that the native code uses layout heuristics which are not easily available to JS to do so. In order to approximate the native heuristic we can assume that if new items are added at the start of the list, it will cause `maintainVisibleContentPosition` to be triggered. This simplifies JS logic a lot as we don't have to track visible items. In the worst case if for some reason our JS heuristic is wrong, it will cause extra cells to be rendered until the next scroll event, or content position will not be maintained (what happens all the time currently). I think this is a good compromise between complexity and accuracy.
We need to find how many items have been added before the first one. To do that we save the key of the first item in state `firstItemKey`. When data changes we can find the index of `firstItemKey` in the new data and that will be the amount we need to adjust the window state by.
Note that this means that keys need to be stable, and using index won't work.
### Add cells to render mask so that previously visible cells stay rendered
Once we have the adjusted number we can save this in a new state value `maintainVisibleContentPositionAdjustment` and add the adjusted cells to the render mask.
This state is then cleared when we receive updated scroll metrics, once the native implementation is done adding the new items and adjusting the content offset.
This value is also only set when `maintainVisibleContentPosition` is set so this makes sure this maintains the currently behavior when that prop is not set.
### Ignore certain updates while scroll metrics are invalid
While the `maintainVisibleContentPositionAdjustment` state is set we know that the current scroll metrics are invalid since they will be updated in the native `ScrollView` implementation. In that case we want to prevent certain code from running.
One example is `onStartReached` that will be called incorrectly while we are waiting for updated scroll metrics.
## Changelog
[General] [Fixed] - Fix VirtualizedList with maintainVisibleContentPosition
Pull Request resolved: https://github.com/facebook/react-native/pull/35993
Test Plan:
Added bidirectional paging to RN tester FlatList example. Note that for this to work RN tester need to be run using old architecture on iOS, to use new architecture it requires https://github.com/facebook/react-native/pull/35319
Using debug mode we can see that virtualization is still working properly, and content position is being maintained.
https://user-images.githubusercontent.com/2677334/163294404-e2eeae5b-e079-4dba-8664-ad280c171ae6.mov
Reviewed By: yungsters
Differential Revision: D45294060
Pulled By: NickGerleman
fbshipit-source-id: 8e5228318886aa75da6ae397f74d1801d40295e8
Summary:
Right now RNTestePage either adds a large spacer to the end of content, unless `noSpacer` is added. But with `noSpacer`, scrolling content may not be reachable because we are putting padding on the wrong container.
This fixes that and removes a few cases where we had multi hundred px empty space in favor of uniformly taking up the parent, and a 10px padding. This also moves the constant margin at the top of RNTesterBlock to the container, so that in the E2E container we can save the 30px.
Changelog:
[Internal]
Reviewed By: javache
Differential Revision: D44197303
fbshipit-source-id: 8dc67f3588bc28316e2fee8d25a0bc59995f1728
Summary:
This change reverts D41745930 (https://github.com/facebook/react-native/commit/2e3dbe9c2fbff52448e2d5a7c1e4c96b1016cf25) as part of a stack to splice back source history which was lost (Git registered the file moves as additions).
It is expected this diff will individually fail. The entire stack should be applied at once.
Changelog: [Internal]
Reviewed By: hoxyq
Differential Revision: D43068113
fbshipit-source-id: c8398629fe5dcc1ca4bf02f550adc00c78a8487a
Summary:
Cleans up a few minor Flow suppression comments in `FlatList`. This reveals a new Flow error that is the result of `FlatList`'s props object being inexact whereas `VirtualizedList`'s props object is exact. For now, I introduce another -- but more specific -- Flow suppression for that type error.
The code changes should not have any consequential behavior change.
Changelog:
[Internal]
Reviewed By: NickGerleman
Differential Revision: D38646228
fbshipit-source-id: f4f9b0ad95323157ff1519353b38e8486adc841d
Summary: Add annotations to function parameters required for Flow's Local Type Inference project. This codemod prepares the codebase to match Flow's new typechecking algorithm. The new algorithm will make Flow more reliable and predictable.
Reviewed By: bradzacher
Differential Revision: D37388949
fbshipit-source-id: cdcbc98035ce9b6994842005ea46df42de54f9b8
Summary:
Followup task for S271544.
There were no tests covering RTL on FlatLists, which would have prevented the above SEV. Adding an RNTester example for this.
Changelog:
[Internal] - Added RNTester example FlatList with RTL
Reviewed By: lunaleaps, javache
Differential Revision: D36601583
fbshipit-source-id: 054ac4eee876a514152f83ecc0522c62337cfea5
Summary:
This diff runs the codemod to add type annotations to function parameters in preparation for Flow's local type inference (LTI) project. I ran the codemod over xplat/js and reverted any files that had flow errors in them. See the list of commands run to see the regeneration of various files.
Changelog:
[Internal][Changed] - Added type annotations
Reviewed By: yungsters
Differential Revision: D32075270
fbshipit-source-id: 6a9cd85aab120b4d9e690bac142a415525dbf298
Summary: Changelog: [Internal] Create FlatList example index for 3 levels of navigation
Reviewed By: charlesbdudley
Differential Revision: D30816721
fbshipit-source-id: a3bdae7f385bab3695a9c2dc6fe3148ebdbd12b4
