Make most modules in Image flow strict-local (#40728)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/40728

Just improving type safety of a bunch of modules in the `Image` directory.

Changelog: [internal]

Reviewed By: NickGerleman

Differential Revision: D50080136

fbshipit-source-id: cbfb89aa01cad3882aa08a8ba637e561017d5db6

packages/react-native/Libraries/Image/AssetSourceResolver.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
+ * @flow strict-local
  * @format
  */
 
@@ -68,7 +68,7 @@ class AssetSourceResolver {
   }
 
   isLoadedFromFileSystem(): boolean {
-    return !!(this.jsbundleUrl && this.jsbundleUrl.startsWith('file://'));
+    return this.jsbundleUrl != null && this.jsbundleUrl?.startsWith('file://');
   }
 
   defaultAsset(): ResolvedAssetSource {
@@ -90,7 +90,7 @@ class AssetSourceResolver {
    * from the devserver
    */
   assetServerURL(): ResolvedAssetSource {
-    invariant(!!this.serverUrl, 'need server to load from');
+    invariant(this.serverUrl != null, 'need server to load from');
     return this.fromSource(
       this.serverUrl +
         getScaledAssetPath(this.asset) +
@@ -114,7 +114,7 @@ class AssetSourceResolver {
    * E.g. 'file:///sdcard/bundle/assets/AwesomeModule/icon@2x.png'
    */
   scaledAssetURLNearBundle(): ResolvedAssetSource {
-    const path = this.jsbundleUrl || 'file://';
+    const path = this.jsbundleUrl ?? 'file://';
     return this.fromSource(
       // Assets can have relative paths outside of the project root.
       // When bundling them we replace `../` with `_` to make sure they
@@ -143,7 +143,7 @@ class AssetSourceResolver {
    * E.g. 'file:///sdcard/AwesomeModule/drawable-mdpi/icon.png'
    */
   drawableFolderInBundle(): ResolvedAssetSource {
-    const path = this.jsbundleUrl || 'file://';
+    const path = this.jsbundleUrl ?? 'file://';
     return this.fromSource(path + getAssetPathInDrawableFolder(this.asset));
   }
 

packages/react-native/Libraries/Image/AssetUtils.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
+ * @flow strict-local
  * @format
  */
 
@@ -14,12 +14,11 @@ let cacheBreaker;
 let warnIfCacheBreakerUnset = true;
 
 export function pickScale(scales: Array<number>, deviceScale?: number): number {
-  if (deviceScale == null) {
-    deviceScale = PixelRatio.get();
-  }
+  const requiredDeviceScale = deviceScale ?? PixelRatio.get();
+
   // Packager guarantees that `scales` array is sorted
   for (let i = 0; i < scales.length; i++) {
-    if (scales[i] >= deviceScale) {
+    if (scales[i] >= requiredDeviceScale) {
       return scales[i];
     }
   }

packages/react-native/Libraries/Image/ImageBackground.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
+ * @flow strict-local
  * @format
  */
 
@@ -45,7 +45,7 @@ import * as React from 'react';
  * ```
  */
 class ImageBackground extends React.Component<ImageBackgroundProps> {
-  setNativeProps(props: Object) {
+  setNativeProps(props: {...}) {
     // Work-around flow
     const viewRef = this._viewRef;
     if (viewRef) {

packages/react-native/Libraries/Image/ImageUtils.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
+ * @flow strict
  * @format
  */
 

packages/react-native/Libraries/Image/resolveAssetSource.js

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @format
- * @flow
+ * @flow strict-local
  */
 
 // Resolves an asset into a `source` for `Image`.
@@ -13,6 +13,7 @@
 'use strict';
 
 import type {ResolvedAssetSource} from './AssetSourceResolver';
+import type {ImageSource} from './ImageSource';
 
 const AssetSourceResolver = require('./AssetSourceResolver');
 const {pickScale} = require('./AssetUtils');
@@ -22,7 +23,7 @@ let _customSourceTransformer, _serverURL, _scriptURL;
 
 let _sourceCodeScriptURL: ?string;
 function getSourceCodeScriptURL(): ?string {
-  if (_sourceCodeScriptURL) {
+  if (_sourceCodeScriptURL != null) {
     return _sourceCodeScriptURL;
   }
 
@@ -38,8 +39,7 @@ function getSourceCodeScriptURL(): ?string {
 function getDevServerURL(): ?string {
   if (_serverURL === undefined) {
     const sourceCodeScriptURL = getSourceCodeScriptURL();
-    const match =
-      sourceCodeScriptURL && sourceCodeScriptURL.match(/^https?:\/\/.*?\//);
+    const match = sourceCodeScriptURL?.match(/^https?:\/\/.*?\//);
     if (match) {
       // jsBundle was loaded from network
       _serverURL = match[0];
@@ -52,19 +52,25 @@ function getDevServerURL(): ?string {
 }
 
 function _coerceLocalScriptURL(scriptURL: ?string): ?string {
-  if (scriptURL) {
-    if (scriptURL.startsWith('assets://')) {
+  let normalizedScriptURL = scriptURL;
+
+  if (normalizedScriptURL != null) {
+    if (normalizedScriptURL.startsWith('assets://')) {
       // android: running from within assets, no offline path to use
       return null;
     }
-    scriptURL = scriptURL.substring(0, scriptURL.lastIndexOf('/') + 1);
-    if (!scriptURL.includes('://')) {
+    normalizedScriptURL = normalizedScriptURL.substring(
+      0,
+      normalizedScriptURL.lastIndexOf('/') + 1,
+    );
+    if (!normalizedScriptURL.includes('://')) {
       // Add file protocol in case we have an absolute file path and not a URL.
       // This shouldn't really be necessary. scriptURL should be a URL.
-      scriptURL = 'file://' + scriptURL;
+      normalizedScriptURL = 'file://' + normalizedScriptURL;
     }
   }
-  return scriptURL;
+
+  return normalizedScriptURL;
 }
 
 function getScriptURL(): ?string {
@@ -84,8 +90,10 @@ function setCustomSourceTransformer(
  * `source` is either a number (opaque type returned by require('./foo.png'))
  * or an `ImageSource` like { uri: '<http location || file path>' }
  */
-function resolveAssetSource(source: any): ?ResolvedAssetSource {
-  if (typeof source === 'object') {
+function resolveAssetSource(source: ?ImageSource): ?ResolvedAssetSource {
+  if (source == null || typeof source === 'object') {
+    // $FlowFixMe[incompatible-exact] `source` doesn't exactly match `ResolvedAssetSource`
+    // $FlowFixMe[incompatible-return] `source` doesn't exactly match `ResolvedAssetSource`
     return source;
   }