refactor: use Buffer.read* to parse payload

index.js

@@ -1,7 +1,7 @@
 // ==UserScript==
 // @name         sup-ytsync
 // @namespace    https://forgejo.sup39.dev/sup39/sup-ytsync/
-// @version      2024-01-30
+// @version      2024-02-03
 // @description  A script to sync Youtube video progress with others via MQTT
 // @author       sup39
 // @match        https://www.youtube.com/watch*
@@ -65,9 +65,6 @@
     };
   }
 
-  // FIXME
-  const Buffer = /** @type{Buffer}*//**@type{any}*/(Uint8Array);
-
   const videoId = new URLSearchParams(window.location.search).get('v');
   if (videoId == null) return;
 
@@ -92,12 +89,12 @@
     const client = mqtt.connect(url, {username, password, clientId});
     client.on('error', e => console.warn('Error occurs on MQTT connection:', e));
 
-    /** @param {DataView} body */
-    function parseTime(body) {
-      if (body.byteLength !== 8) {
+    /** @param {Buffer} payload */
+    function parseTime(payload) {
+      if (payload.byteLength !== 8) {
         throw new Error('Invalid payload');
       }
-      return body.getFloat64(0);
+      return payload.readDoubleBE(0);
     }
 
     client.on('connect', () => {
@@ -106,12 +103,16 @@
       const video = Video(videoElement, (command, state) => {
         const {currentTime: t} = state;
         console.debug(`Broadcast video sync command [${command}]`, t);
-        const payload = new Buffer(8);
+        const payload = new Uint8Array(8);
         new DataView(payload.buffer).setFloat64(0, t);
-        client.publish(`${topicPrefix}${clientId}/${command}`, payload);
+        client.publish(
+          `${topicPrefix}${clientId}/${command}`,
+          // FIXME
+          /**@type{Buffer}*/(/**@type{unknown}*/(payload)),
+        );
       });
 
-      client.on('message', (/**@type{string}*/topic, /**@type{Uint8Array}*/payload) => {
+      client.on('message', (topic, payload) => {
         if (!topic.startsWith(topicPrefix)) {
           return console.warn('Unexpected MQTT message', {topic, payload});
         }
@@ -119,21 +120,14 @@
         // ignore command sent by self
         if (commander === clientId) return;
 
-        /** DataView of payload */
-        const body = new DataView(
-          payload.buffer,
-          payload.byteOffset,
-          payload.byteLength,
-        );
-
         try {
           if (command === 'play') {
-            const t = parseTime(body);
+            const t = parseTime(payload);
             console.debug(`Received command [${command}]`, t);
             video.seek(t);
             video.play();
           } else if (command === 'pause') {
-            const t = parseTime(body);
+            const t = parseTime(payload);
             console.debug(`Received command [${command}]`, t);
             video.seek(t);
             video.pause();
@@ -145,7 +139,7 @@
              *  => need to update current time
              */
             if (video.isPaused) {
-              const t = parseTime(body);
+              const t = parseTime(payload);
               console.debug(`Received command [${command}]`, t);
               video.seek(t);
             }