Introduce flow type to differentiate between HostComponent, NativeMethodsMixin, and NativeComponent

Summary:
In React Native there are three types of "Native" components.

```
createReactClass with NativeMethodsMixin
```
```
class MyComponent extends ReactNative.NativeComponent
```
```
requireNativeComponent('RCTView')
```

The implementation for how to handle all three of these exists in the React Native Renderer. Refs attached to components created via these methods provide a set of functions such as
```
.measure
.measureInWindow
.measureLayout
.setNativeProps
```

These methods have been used for our core components in the repo to provide a consistent API. Many of the APIs in React Native require a `reactTag` to a host component. This is acquired by calling `findNodeHandle` with any component. `findNodeHandle` works with the first two approaches.

For a lot of our new Fabric APIs, we will require passing a ref to a HostComponent directly instead of relying on `findNodeHandle` to tunnel through the component tree as that behavior isn't safe with React concurrent mode.

The goal of this change is to enable us to differentiate between components created with `requireNativeComponent` and the other types. This will be needed to be able to safely type the new APIs.

For existing components that should support being a host component but need to use some JS behavior in a wrapper, they should use `forwardRef`. The majority of React Native's core components were migrated to use `forwardRef` last year. Components that can't use forwardRef will need to have a method like `getNativeRef()` to get access to the underlying host component ref.

Note, we will need follow up changes as well as changes to the React Renderer in the React repo to fully utilize this new type.

Changelog:
[Internal] Flow type to differentiate between HostComponent and NativeMethodsMixin and NativeComponent

Reviewed By: jbrown215

Differential Revision: D17551089

fbshipit-source-id: 7a30b4bb4323156c0b2465ca41fcd05f4315becf

Author: elicwhite

Libraries/Components/RefreshControl/__mocks__/RefreshControlMock.js

@@ -14,14 +14,18 @@ const React = require('react');
 
 const requireNativeComponent = require('../../../ReactNative/requireNativeComponent');
 
-const RCTRefreshControl = requireNativeComponent('RCTRefreshControl');
+import type {HostComponent} from '../../../Renderer/shims/ReactNativeTypes';
+
+const RCTRefreshControl: HostComponent<mixed> = requireNativeComponent<mixed>(
+  'RCTRefreshControl',
+);
 
 class RefreshControlMock extends React.Component<{}> {
   static latestRef: ?RefreshControlMock;
   componentDidMount() {
     RefreshControlMock.latestRef = this;
   }
-  render(): React.Element<string> {
+  render(): React.Element<typeof RCTRefreshControl> {
     return <RCTRefreshControl />;
   }
 }

Libraries/Components/ScrollResponder.js

@@ -28,6 +28,7 @@ import type {PressEvent, ScrollEvent} from '../Types/CoreEventTypes';
 import type {Props as ScrollViewProps} from './ScrollView/ScrollView';
 import type {KeyboardEvent} from './Keyboard/Keyboard';
 import type EmitterSubscription from '../vendor/emitter/EmitterSubscription';
+import type {HostComponent} from '../Renderer/shims/ReactNativeTypes';
 
 /**
  * Mixin that can be integrated in order to handle scrolling that plays well
@@ -543,6 +544,7 @@ const ScrollResponderMixin = {
   scrollResponderScrollNativeHandleToKeyboard: function<T>(
     nodeHandle:
       | number
+      | React.ElementRef<HostComponent<T>>
       | React.ElementRef<Class<ReactNative.NativeComponent<T>>>,
     additionalOffset?: number,
     preventNegativeScrollOffset?: boolean,

Libraries/Components/ScrollView/__mocks__/ScrollViewMock.js

@@ -17,12 +17,16 @@ const View = require('../../View/View');
 
 const requireNativeComponent = require('../../../ReactNative/requireNativeComponent');
 
-const RCTScrollView = requireNativeComponent('RCTScrollView');
+import type {HostComponent} from '../../../Renderer/shims/ReactNativeTypes';
+
+const RCTScrollView: HostComponent<mixed> = requireNativeComponent<mixed>(
+  'RCTScrollView',
+);
 
 const ScrollViewComponent: $FlowFixMe = jest.genMockFromModule('../ScrollView');
 
 class ScrollViewMock extends ScrollViewComponent {
-  render(): React.Element<string> {
+  render(): React.Element<typeof RCTScrollView> {
     return (
       <RCTScrollView {...this.props}>
         {this.props.refreshControl}

Libraries/Components/TextInput/TextInput.js

@@ -32,6 +32,7 @@ import type {ColorValue} from '../../StyleSheet/StyleSheetTypes';
 import type {ViewProps} from '../View/ViewPropTypes';
 import type {SyntheticEvent, ScrollEvent} from '../../Types/CoreEventTypes';
 import type {PressEvent} from '../../Types/CoreEventTypes';
+import type {HostComponent} from '../../Renderer/shims/ReactNativeTypes';
 
 let AndroidTextInput;
 let RCTMultilineTextInputView;
@@ -904,9 +905,7 @@ const TextInput = createReactClass({
     this._inputRef = ref;
   },
 
-  getNativeRef: function(): ?React.ElementRef<
-    Class<ReactNative.NativeComponent<mixed>>,
-  > {
+  getNativeRef: function(): ?React.ElementRef<HostComponent<mixed>> {
     return this._inputRef;
   },
 
@@ -1230,9 +1229,7 @@ const TextInput = createReactClass({
 class InternalTextInputType extends ReactNative.NativeComponent<Props> {
   clear() {}
 
-  getNativeRef(): ?React.ElementRef<
-    Class<ReactNative.NativeComponent<mixed>>,
-  > {}
+  getNativeRef(): ?React.ElementRef<HostComponent<mixed>> {}
 
   // $FlowFixMe
   isFocused(): boolean {}

Libraries/Components/View/ViewNativeComponent.js

@@ -11,17 +11,15 @@
 'use strict';
 
 const Platform = require('../../Utilities/Platform');
-const ReactNative = require('../../Renderer/shims/ReactNative');
 const ReactNativeViewViewConfigAndroid = require('./ReactNativeViewViewConfigAndroid');
 
 const registerGeneratedViewConfig = require('../../Utilities/registerGeneratedViewConfig');
 const requireNativeComponent = require('../../ReactNative/requireNativeComponent');
 
 import type {ViewProps} from './ViewPropTypes';
+import type {HostComponent} from '../../Renderer/shims/ReactNativeTypes';
 
-export type ViewNativeComponentType = Class<
-  ReactNative.NativeComponent<ViewProps>,
->;
+export type ViewNativeComponentType = HostComponent<ViewProps>;
 
 let NativeViewComponent;
 let viewConfig:

Libraries/Image/Image.android.js

@@ -207,15 +207,15 @@ async function queryCache(
   return await ImageLoader.queryCache(urls);
 }
 
-declare class ImageComponentType extends ReactNative.NativeComponent<ImagePropsType> {
-  static getSize: typeof getSize;
-  static getSizeWithHeaders: typeof getSizeWithHeaders;
-  static prefetch: typeof prefetch;
-  static abortPrefetch: typeof abortPrefetch;
-  static queryCache: typeof queryCache;
-  static resolveAssetSource: typeof resolveAssetSource;
-  static propTypes: typeof ImageProps;
-}
+type ImageComponentStatics = $ReadOnly<{|
+  getSize: typeof getSize,
+  getSizeWithHeaders: typeof getSizeWithHeaders,
+  prefetch: typeof prefetch,
+  abortPrefetch: typeof abortPrefetch,
+  queryCache: typeof queryCache,
+  resolveAssetSource: typeof resolveAssetSource,
+  propTypes: typeof ImageProps,
+|}>;
 
 /**
  * A React component for displaying different types of images,
@@ -224,10 +224,7 @@ declare class ImageComponentType extends ReactNative.NativeComponent<ImagePropsT
  *
  * See https://facebook.github.io/react-native/docs/image.html
  */
-let Image = (
-  props: ImagePropsType,
-  forwardedRef: ?React.Ref<'RCTTextInlineImage' | 'ImageViewNativeComponent'>,
-) => {
+let Image = (props: ImagePropsType, forwardedRef) => {
   let source = resolveAssetSource(props.source);
   const defaultSource = resolveAssetSource(props.defaultSource);
   const loadingIndicatorSource = resolveAssetSource(
@@ -303,7 +300,12 @@ let Image = (
   );
 };
 
-Image = React.forwardRef(Image);
+Image = React.forwardRef<
+  ImagePropsType,
+  | React.ElementRef<typeof TextInlineImageNativeComponent>
+  | React.ElementRef<typeof ImageViewNativeComponent>,
+>(Image);
+
 Image.displayName = 'Image';
 
 /**
@@ -379,7 +381,9 @@ const styles = StyleSheet.create({
   },
 });
 
-/* $FlowFixMe(>=0.89.0 site=react_native_android_fb) This comment suppresses an
- * error found when Flow v0.89 was deployed. To see the error, delete this
- * comment and run Flow. */
-module.exports = (Image: Class<ImageComponentType>);
+module.exports = ((Image: any): React.AbstractComponent<
+  ImagePropsType,
+  | React.ElementRef<typeof TextInlineImageNativeComponent>
+  | React.ElementRef<typeof ImageViewNativeComponent>,
+> &
+  ImageComponentStatics);

Libraries/Image/Image.ios.js

@@ -19,14 +19,15 @@ const flattenStyle = require('../StyleSheet/flattenStyle');
 const requireNativeComponent = require('../ReactNative/requireNativeComponent');
 const resolveAssetSource = require('./resolveAssetSource');
 
-const ImageViewManager = NativeModules.ImageViewManager;
-
-const RCTImageView = requireNativeComponent('RCTImageView');
-
 import type {ImageProps as ImagePropsType} from './ImageProps';
-
+import type {HostComponent} from '../Renderer/shims/ReactNativeTypes';
 import type {ImageStyleProp} from '../StyleSheet/StyleSheet';
 
+const ImageViewManager = NativeModules.ImageViewManager;
+const RCTImageView: HostComponent<mixed> = requireNativeComponent(
+  'RCTImageView',
+);
+
 function getSize(
   uri: string,
   success: (width: number, height: number) => void,
@@ -70,14 +71,14 @@ async function queryCache(
   return await ImageViewManager.queryCache(urls);
 }
 
-declare class ImageComponentType extends ReactNative.NativeComponent<ImagePropsType> {
-  static getSize: typeof getSize;
-  static getSizeWithHeaders: typeof getSizeWithHeaders;
-  static prefetch: typeof prefetch;
-  static queryCache: typeof queryCache;
-  static resolveAssetSource: typeof resolveAssetSource;
-  static propTypes: typeof DeprecatedImagePropType;
-}
+type ImageComponentStatics = $ReadOnly<{|
+  getSize: typeof getSize,
+  getSizeWithHeaders: typeof getSizeWithHeaders,
+  prefetch: typeof prefetch,
+  queryCache: typeof queryCache,
+  resolveAssetSource: typeof resolveAssetSource,
+  propTypes: typeof DeprecatedImagePropType,
+|}>;
 
 /**
  * A React component for displaying different types of images,
@@ -86,10 +87,7 @@ declare class ImageComponentType extends ReactNative.NativeComponent<ImagePropsT
  *
  * See https://facebook.github.io/react-native/docs/image.html
  */
-let Image = (
-  props: ImagePropsType,
-  forwardedRef: ?React.Ref<'RCTImageView'>,
-) => {
+let Image = (props: ImagePropsType, forwardedRef) => {
   const source = resolveAssetSource(props.source) || {
     uri: undefined,
     width: undefined,
@@ -140,7 +138,9 @@ let Image = (
   );
 };
 
-Image = React.forwardRef(Image);
+Image = React.forwardRef<ImagePropsType, React.ElementRef<typeof RCTImageView>>(
+  Image,
+);
 Image.displayName = 'Image';
 
 /**
@@ -206,7 +206,8 @@ const styles = StyleSheet.create({
   },
 });
 
-/* $FlowFixMe(>=0.89.0 site=react_native_ios_fb) This comment suppresses an
- * error found when Flow v0.89 was deployed. To see the error, delete this
- * comment and run Flow. */
-module.exports = (Image: Class<ImageComponentType>);
+module.exports = ((Image: any): React.AbstractComponent<
+  ImagePropsType,
+  React.ElementRef<typeof RCTImageView>,
+> &
+  ImageComponentStatics);

Libraries/Image/ImageViewNativeComponent.js

@@ -5,13 +5,17 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @format
- * @flow
+ * @flow strict-local
  */
 
 'use strict';
 
 const requireNativeComponent = require('../ReactNative/requireNativeComponent');
 
-const ImageViewNativeComponent: string = requireNativeComponent('RCTImageView');
+import type {HostComponent} from '../Renderer/shims/ReactNativeTypes';
+
+const ImageViewNativeComponent: HostComponent<mixed> = requireNativeComponent<mixed>(
+  'RCTImageView',
+);
 
 module.exports = ImageViewNativeComponent;

Libraries/Image/TextInlineImageNativeComponent.js

@@ -5,13 +5,16 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @format
- * @flow
+ * @flow strict-local
  */
 
 'use strict';
 
 const requireNativeComponent = require('../ReactNative/requireNativeComponent');
+import type {HostComponent} from '../Renderer/shims/ReactNativeTypes';
 
-const TextInlineImage: string = requireNativeComponent('RCTTextInlineImage');
+const TextInlineImage: HostComponent<mixed> = requireNativeComponent<mixed>(
+  'RCTTextInlineImage',
+);
 
 module.exports = TextInlineImage;

Libraries/ReactNative/requireNativeComponent.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow strict-local
+ * @flow
  * @format
  */
 
@@ -13,6 +13,8 @@
 const createReactNativeComponentClass = require('../Renderer/shims/createReactNativeComponentClass');
 const getNativeComponentAttributes = require('./getNativeComponentAttributes');
 
+import type {HostComponent} from '../Renderer/shims/ReactNativeTypes';
+
 /**
  * Creates values that can be used like React components which represent native
  * view managers. You should create JavaScript modules that wrap these values so
@@ -21,9 +23,10 @@ const getNativeComponentAttributes = require('./getNativeComponentAttributes');
  *   const View = requireNativeComponent('RCTView');
  *
  */
-const requireNativeComponent = (uiViewClassName: string): string =>
-  createReactNativeComponentClass(uiViewClassName, () =>
+
+const requireNativeComponent = <T>(uiViewClassName: string): HostComponent<T> =>
+  ((createReactNativeComponentClass(uiViewClassName, () =>
     getNativeComponentAttributes(uiViewClassName),
-  );
+  ): any): HostComponent<T>);
 
 module.exports = requireNativeComponent;