docs(react): update react functional component tutorial

docs/guides/react.md

@@ -12,43 +12,55 @@ import "video.js/dist/video-js.css";
 export const VideoJS = ( props ) => {
 
   const videoRef = React.useRef(null);
-  const { options } = props;
+  const playerRef = React.useRef(null);
+  const { options, onReady } = props;
 
-  // This separate functional component fixes the removal of the videoelement 
-  // from the DOM when calling the dispose() method on a player
-  const VideoHtml = ( props ) => (
-    <div data-vjs-player>
-      <video ref={videoRef} className="video-js vjs-big-play-centered" />
-    </div>
-  );
+  React.useEffect(() => {
+    // make sure Video.js player is only initialized once
+    if (!playerRef.current) {
+      const videoElement = videoRef.current;
+      if (!videoElement) return;
 
-  React.useEffect( () => {
-    const videoElement = videoRef.current;
-    let player;
-    if( videoElement ) {
-      player = videojs( videoElement, options, () => {
+      const player = playerRef.current = videojs(videoElement, options, () => {
         console.log("player is ready");
+        onReady && onReady(player);
       });
+    } else {
+      // you can update player here [update player through props]
+      // const player = playerRef.current;
+      // player.autoplay(options.autoplay);
+      // player.src(options.sources);
     }
+  }, [options]);
+
+  // Dispose the Video.js player when the functional component unmounts
+  React.useEffect(() => {
     return () => {
-      if( player ) {
-        player.dispose();
+      if (playerRef.current) {
+        playerRef.current.dispose();
+        playerRef.current = null;
       }
-    }
-  }, [options]);
+    };
+  }, []);
 
-  return (<VideoHtml />);
+  return (
+    <div data-vjs-player>
+      <video ref={videoRef} className="video-js vjs-big-play-centered" />
+    </div>
+  );
 }
-export default VideoJS;
 
+export default VideoJS;
 ```
 
 You can then use it like this: (see [options guide][options] for option information)
+
 ```jsx
 import React from "react";
 import VideoJS from './VideoJS' // point to where the functional component is stored
 
 const App = () => {
+  const playerRef = React.useRef(null);
 
   const videoJsOptions = { // lookup the options in the docs for more options
     autoplay: true,
@@ -60,18 +72,40 @@ const App = () => {
       type: 'video/mp4'
     }]
   }
-
+
+  const handlePlayerReady = (player) => {
+    playerRef.current = player;
+
+    // you can handle player events here
+    player.on('waiting', () => {
+      console.log('player is waiting');
+    });
+
+    player.on('dispose', () => {
+      console.log('player will dispose');
+    });
+  };
+
+  // const changePlayerOptions = () => {
+  //   // you can update the player through the Video.js player instance
+  //   if (!playerRef.current) {
+  //     return;
+  //   }
+  //   // [update player through instance's api]
+  //   playerRef.current.src([{src: 'http://ex.com/video.mp4', type: 'video/mp4'}]);
+  //   playerRef.current.autoplay(false);
+  // };
+
   return (
     <>
       <div>Rest of app here</div>
-      
-      <VideoJS options={videoJsOptions}/>
-      
+
+      <VideoJS options={videoJsOptions} onReady={handlePlayerReady} />
+
       <div>Rest of app here</div>
     </>
   );
 }
-
 ```
 
 ## React Class Component Example
@@ -103,7 +137,7 @@ export default class VideoPlayer extends React.Component {
   // see https://github.com/videojs/video.js/pull/3856
   render() {
     return (
-      <div>	
+      <div>
         <div data-vjs-player>
           <video ref={ node => this.videoNode = node } className="video-js"></video>
         </div>
@@ -127,9 +161,8 @@ const videoJsOptions = {
 
 return <VideoPlayer { ...videoJsOptions } />
 ```
-[options]: /docs/guides/options.md
-
 
+[options]: /docs/guides/options.md
 
 ## Using a React Component as a Video JS Component
 
@@ -178,7 +211,7 @@ class vjsEpisodeList extends vjsComponent {
     player.ready(() => {
       this.mount();
     });
-    
+
     /* Remove React root when component is destroyed */
     this.on("dispose", () => {
       ReactDOM.unmountComponentAtNode(this.el())