Files
react-native/Libraries/Components/ScrollView/__tests__/ScrollView-test.js
T
Kacie Bawiec d2f314af75 Make ScrollView use ForwardRef
Summary:
Have ScrollView use forwardRef so that the host component methods like `measure` and `measureLayout` are available without having to call `getNativeScrollRef`. Instead, you can use `<ScrollView ref={myRef} />` and directly call all methods of ScrollView and host components on `myRef`.

Previous usage:
```
const myRef = React.createRef<React.ElementRef<typeof ScrollView>>();
<ScrollView ref={myRef} />

const innerViewRef = myRef.current.getNativeScrollRef();

innerViewRef.measure();
```
New usage:
```
const myRef = React.createRef<React.ElementRef<typeof View>>();
<ScrollView ref={myRef} />

// now, myRef.current can be used directly as the ref
myRef.current.measure();
myRef.current.measureLayout();

// Additionally, myRef still has access to ScrollView methods
myRef.current.scrollTo(...);
```

Changes:

* Added deprecation warnings to ScrollView methods `getNativeScrollRef`, `getScrollableNode`, and `getScrollResponder`
* Added the forwardRef call to create `ForwardedScrollView` - this takes in `ref` and passes it into the class ScrollView as `scrollViewRef`.
* Forwarded the ref to the native scroll view using `setAndForwardRef`.
* Added statics onto `ForwardedScrollView` so that `ScrollView.Context` can still be accessed.
* Added type `ScrollViewImperativeMethods`, which lists the public methods of ScrollView.
* Converted all public methods of ScrollView to arrow functions. This is because they need to be bound to the forwarded ref.
* Bound all public methods of ScrollView to the forwarded ref in the `setAndForwardRef` call.
* Flow typed the final output (ForwardedScrollView) as an abstract component that takes in the props of the `ScrollView` class, and has all methods of both the inner host component (`measure`, `measureLayout`, etc) and the public methods (`scrollTo`, etc).

Changes to mockScrollView:
* Changed mockScrollView to be able to mock the function component instead of a class component
* Updated necessary tests

Changelog:
[General] [Changed] - Make ScrollView use forwardRef

Reviewed By: TheSavior

Differential Revision: D19304480

fbshipit-source-id: 6c359897526d9d5ac6bc6ab6d5f9d82bfc0d8af4
2020-03-26 16:53:46 -07:00

52 lines
1.4 KiB
JavaScript

/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
* @emails oncall+react_native
* @flow-strict
*/
'use strict';
const React = require('react');
const ScrollView = require('../ScrollView');
const ReactNativeTestTools = require('../../../Utilities/ReactNativeTestTools');
const ReactTestRenderer = require('react-test-renderer');
const View = require('../../View/View');
const Text = require('../../../Text/Text');
describe('<ScrollView />', () => {
it('should render as expected', () => {
ReactNativeTestTools.expectRendersMatchingSnapshot(
'ScrollView',
() => (
<ScrollView>
<View>
<Text>Hello World!</Text>
</View>
</ScrollView>
),
() => {
jest.dontMock('../ScrollView');
},
);
});
it('should mock native methods and instance methods when mocked', () => {
jest.resetModules();
jest.mock('../ScrollView');
const ref = React.createRef();
ReactTestRenderer.create(<ScrollView ref={ref} />);
expect(ref.current != null && ref.current.measure).toBeInstanceOf(
jest.fn().constructor,
);
expect(ref.current != null && ref.current.scrollTo).toBeInstanceOf(
jest.fn().constructor,
);
});
});