Fix isSelected not being passed to FlatList.renderItem

[tido64]

• I am removing an existing difference between facebook/react-native and microsoft/react-native-macos 👍
• I am cherry-picking a change from Facebook's react-native into microsoft/react-native-macos 👍
• I am making a fix / change for the macOS implementation of react-native
• I am making a change required for Microsoft usage of react-native

Summary

FlatList doesn't pass isSelected to renderItem.

Resolves #462

Changelog

[macOS] [Fixed] - Fix isSelected not being passed to FlatList.renderItem

Test Plan

1. Patch RNTester/js/examples/FlatList/FlatListExample.js to output isSelected (see patch below)
2. Go to RNTester > FlatList
3. Observe that undefined is no longer output, but proper boolean values

diff --git a/RNTester/js/examples/FlatList/FlatListExample.js b/RNTester/js/examples/FlatList/FlatListExample.js
index 733285229..4936ee212 100644
--- a/RNTester/js/examples/FlatList/FlatListExample.js
+++ b/RNTester/js/examples/FlatList/FlatListExample.js
@@ -191,6 +191,7 @@ class FlatListExample extends React.PureComponent<Props, State> {
       renderItem: undefined,
       [flatListPropKey]: ({item, isSelected, separators}) => {
         // TODO(macOS ISS#2323203)
+        console.log(JSON.stringify(item), isSelected);
         return (
           <ItemComponent
             item={item}

Microsoft Reviewers: Open in CodeFlow

[elicwhite]

Thanks!