[Bugfix][FlatList] Objects as props trigger invariant errors

[eballeste]

Motivation

Fixes invariant errors introduced in ad733ad triggered when using objects for certain FlatList props, leverages fbjs areEqual to test for equality.

Original Issue:
#16710

Test Plan

Setting a value to viewAreaCoveragePercentThreshold key of viewabilityConfig prop should no longer trigger invariant error.

<FlatList
    ItemSeparatorComponent={() => <separator />}
    ListEmptyComponent={() => <empty />}
    ListFooterComponent={() => <footer />}
    ListHeaderComponent={() => <header />}
    data={new Array(5).fill().map((_, ii) => ({id: String(ii)}))}
    keyExtractor={(item, index) => item.id}
    getItemLayout={({index}) => ({length: 50, offset: index * 50})}
    numColumns={2}
    refreshing={false}
    onRefresh={jest.fn()}
    renderItem={({item}) => <item value={item.id} />}
    viewabilityConfig={{ viewAreaCoveragePercentThreshold: 50 }}
  />,

Release Notes

[pull-bot]

@facebook-github-bot label Android

Generated by 🚫 dangerJS

[eslint-bot]

prettier/prettier: Replace nextProps.viewabilityConfigCallbackPairs,·this.props.viewabilityConfigCallbackPairs with ⏎········nextProps.viewabilityConfigCallbackPairs,⏎········this.props.viewabilityConfigCallbackPairs,⏎······

[eballeste]

why is it pointing to the prev version of the diff?

[eslint-bot]

prettier/prettier: Insert ⏎·

[eslint-bot]

prettier/prettier: Replace nextProps.onViewableItemsChanged,·this.props.onViewableItemsChanged with ⏎········nextProps.onViewableItemsChanged,⏎········this.props.onViewableItemsChanged,⏎······

[eballeste]

???

[shergin]

@eballeste Please, obey Prettier. 😄

[eslint-bot]

prettier/prettier: Insert ,

[eballeste]

???

[eslint-bot]

no-trailing-spaces: Trailing spaces not allowed.

[eslint-bot]

prettier/prettier: Delete ·

[eballeste]

???

[eslint-bot]

no-trailing-spaces: Trailing spaces not allowed.

[eslint-bot]

prettier/prettier: Delete ·

[eballeste]

???

[eslint-bot]

prettier/prettier: Insert ,

[eballeste]

???

[eballeste]

@shergin, @eslint-bot is confusing! sometimes it points to the previous version of a diff. why is that?

[eballeste]

gonna close this, this is my first PR and I have no idea what eslint-bot is doing and honestly it's kind of embarrassing.

also, to bypass this error, just declare the viewabilityConfig as a constant outside of the render method.