Fix ScrollView getInnerViewNode and getInnerViewRef ref methods

[vshab]

Summary

Currently ScrollView ref's getInnerViewNode and getInnerViewRef are unbound and don't work as expected returning empty values. The origin of this problem probably is issued by d2f314a

Working example of the problem is available here: https://github.com/vshab/RNGetInnerViewBug

This PR binds getInnerViewNode and getInnerViewRef to ScrollView and adds test checking the value of getInnerViewRef.

Before:

After:

Changelog

[JavaScript] [Fixed] - ScrollView: Fix getInnerViewNode and getInnerViewRef ref methods

Test Plan

1. The test checking the value of getInnerViewRef is added.
2. Example app demonstrating the problem is provided with before/after screenshots.

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Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 2a175b1

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[elicwhite]

The other methods aren't bound either are they? Is the behavior of this method inconsistent with the behavior of the other methods? The functions on refs in React Native are pretty much all not bound to avoid creating new functions or breaking referential equality on every render

[vshab]

@TheSavior
Hello!

The other methods aren't bound either are they?

Other methods are bound because they are defined as arrow function class properties. See https://github.com/facebook/react-native/blob/master/Libraries/Components/ScrollView/ScrollView.js#L802 for example

Is the behavior of this method inconsistent with the behavior of the other methods?

Yes. Currently getInnerViewNode and getInnerViewRef are just unusable. Check the example: https://github.com/vshab/RNGetInnerViewBug
I think it's a regression introduced by d2f314a. It used to work before

The functions on refs in React Native are pretty much all not bound to avoid creating new functions or breaking referential equality on every render

As I said before all other methods are arrow function preserving this and only getInnerViewNode and getInnerViewRef are regular class methods so they have different call behaviour I think.

[elicwhite]

Should the fix be to make these functions arrow functions as well instead of .bind()?

[vshab]

If you say so :)
I just wanted to make a change that affects as little parts as possible.

[vshab]

@TheSavior I replaced bind with arrow functions.

[vshab]

@TheSavior Hello!

Anything else should be done to merge it?

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@kacieb has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@kacieb merged this pull request in 6e36d04.