fix(JS): improve loader api to allow function call instead of component (#4171)

docs/pages/component/props.mdx

@@ -518,14 +518,29 @@ Speed at which the media should play.
 
 <PlatformsList types={['All']} />
 
-Allows you to create custom components to display while the video is loading. If `renderLoader` is provided, `poster` and `posterResizeMode` will be ignored.
+Allows you to create custom components to display while the video is loading.
+If `renderLoader` is provided, `poster` and `posterResizeMode` will be ignored.
+renderLoader is either a component or a function returning a component.
+It is recommended to use the function for optimization matter.
+
+`renderLoader` function be called with parameters of type `ReactVideoRenderLoaderProps` to be able to adapt loader 
+
+```typescript
+interface ReactVideoRenderLoaderProps {
+  source?: ReactVideoSource;                /// source of the video
+  style?: StyleProp<ImageStyle>;            /// style to apply
+  resizeMode?: EnumValues<VideoResizeMode>; /// resizeMode provided to the video component
+}
+````
+
+Sample:
 
 ```javascript
 <Video>
-  renderLoader={
+  renderLoader={() => (
     <View>
       <Text>Custom Loader</Text>
-    </View>
+    </View>)
   }
 </Video>
 ````

examples/basic/src/VideoPlayer.tsx

@@ -236,6 +236,18 @@ const VideoPlayer: FC<Props> = ({}) => {
     Platform.OS === 'ios' && setPaused(true);
   };
 
+  const _renderLoader = showPoster ? () => <VideoLoader /> : undefined;
+
+  const _subtitleStyle = {subtitlesFollowVideo: true};
+  const _controlsStyles = {
+    hideNavigationBarOnFullScreenMode: true,
+    hideNotificationBarOnFullScreenMode: true,
+  };
+  const _bufferConfig = {
+    ...bufferConfig,
+    cacheSizeMB: useCache ? 200 : 0,
+  }
+
   return (
     <View style={styles.container}>
       <StatusBar animated={true} backgroundColor="black" hidden={false} />
@@ -278,21 +290,15 @@ const VideoPlayer: FC<Props> = ({}) => {
             selectedAudioTrack={selectedAudioTrack}
             selectedVideoTrack={selectedVideoTrack}
             playInBackground={false}
-            bufferConfig={{
-              ...bufferConfig,
-              cacheSizeMB: useCache ? 200 : 0,
-            }}
+            bufferConfig={_bufferConfig}
             preventsDisplaySleepDuringVideoPlayback={true}
-            renderLoader={showPoster ? <VideoLoader /> : undefined}
+            renderLoader={_renderLoader}
             onPlaybackRateChange={onPlaybackRateChange}
             onPlaybackStateChanged={onPlaybackStateChanged}
             bufferingStrategy={BufferingStrategyType.DEFAULT}
             debug={{enable: true, thread: true}}
-            subtitleStyle={{subtitlesFollowVideo: true}}
-            controlsStyles={{
-              hideNavigationBarOnFullScreenMode: true,
-              hideNotificationBarOnFullScreenMode: true,
-            }}
+            subtitleStyle={_subtitleStyle}
+            controlsStyles={_controlsStyles}
           />
         </TouchableOpacity>
       )}

src/Video.tsx

@@ -127,8 +127,18 @@ const Video = forwardRef<VideoRef, ReactVideoProps>(
 
     const isPosterDeprecated = typeof poster === 'string';
 
+    const _renderLoader = useMemo(
+      () =>
+        !renderLoader
+          ? undefined
+          : renderLoader instanceof Function
+          ? renderLoader
+          : () => renderLoader,
+      [renderLoader],
+    );
+
     const hasPoster = useMemo(() => {
-      if (renderLoader) {
+      if (_renderLoader) {
         return true;
       }
 
@@ -137,7 +147,7 @@ const Video = forwardRef<VideoRef, ReactVideoProps>(
       }
 
       return !!poster?.source;
-    }, [isPosterDeprecated, poster, renderLoader]);
+    }, [isPosterDeprecated, poster, _renderLoader]);
 
     const [showPoster, setShowPoster] = useState(hasPoster);
 
@@ -688,15 +698,23 @@ const Video = forwardRef<VideoRef, ReactVideoProps>(
       }
 
       // render poster
-      if (renderLoader && (poster || posterResizeMode)) {
+      if (_renderLoader && (poster || posterResizeMode)) {
         console.warn(
           'You provided both `renderLoader` and `poster` or `posterResizeMode` props. `renderLoader` will be used.',
         );
       }
 
       // render loader
-      if (renderLoader) {
-        return <View style={StyleSheet.absoluteFill}>{renderLoader}</View>;
+      if (_renderLoader) {
+        return (
+          <View style={StyleSheet.absoluteFill}>
+            {_renderLoader({
+              source: source,
+              style: posterStyle,
+              resizeMode: resizeMode,
+            })}
+          </View>
+        );
       }
 
       return (
@@ -711,8 +729,10 @@ const Video = forwardRef<VideoRef, ReactVideoProps>(
       isPosterDeprecated,
       poster,
       posterResizeMode,
-      renderLoader,
+      _renderLoader,
       showPoster,
+      source,
+      resizeMode,
     ]);
 
     const _style: StyleProp<ViewStyle> = useMemo(

src/types/video.ts

@@ -7,6 +7,7 @@ import type {
   ViewStyle,
   ImageRequireSource,
   ImageURISource,
+  ImageStyle,
 } from 'react-native';
 import type {ReactNode} from 'react';
 import type VideoResizeMode from './ResizeMode';
@@ -254,6 +255,12 @@ export type ControlsStyles = {
   hideNotificationBarOnFullScreenMode?: boolean;
 };
 
+export interface ReactVideoRenderLoaderProps {
+  source?: ReactVideoSource;
+  style?: StyleProp<ImageStyle>;
+  resizeMode?: EnumValues<VideoResizeMode>;
+}
+
 export interface ReactVideoProps extends ReactVideoEvents, ViewProps {
   source?: ReactVideoSource;
   /** @deprecated Use source.drm */
@@ -295,7 +302,7 @@ export interface ReactVideoProps extends ReactVideoEvents, ViewProps {
   preventsDisplaySleepDuringVideoPlayback?: boolean;
   progressUpdateInterval?: number;
   rate?: number;
-  renderLoader?: ReactNode;
+  renderLoader?: ReactNode | ((arg0: ReactVideoRenderLoaderProps) => ReactNode);
   repeat?: boolean;
   reportBandwidth?: boolean; //Android
   resizeMode?: EnumValues<VideoResizeMode>;