Make work more reliably in Firefox

app/scripts/background.js

@@ -1,21 +1,44 @@
+import delay from 'delay';
+
+async function tryUntilItWorks(func, delayBetweenTries = 1, maxTries = 10) {
+	for (let i = 0; i < maxTries; i++) {
+		try {
+			await func();
+			return;
+		} catch (err) {
+			await delay(delayBetweenTries);
+			continue;
+		}
+	}
+}
+
 async function onHeadersReceived({ responseHeaders, url, tabId }) {
 	const isAudio = responseHeaders.some(header =>
 		header.name === 'Content-Type' && header.value.startsWith('audio/')
 	);
 
 	if (isAudio) {
-		browser.tabs.executeScript(tabId, {
-			runAt: 'document_end',
-			file: '/scripts/contentscript.js',
-		});
-		browser.tabs.insertCSS(tabId, {
+		// Avoid any short glitch of sound (observed in Firefox) before our injected script executes.
+		await browser.tabs.update(tabId, { muted: true });
+
+		// Too quickly executing the script may fail (bug in Firefox), so we retry if necessary.
+		await tryUntilItWorks(() => browser.tabs.executeScript(tabId, {
+				runAt: 'document_end',
+				file: '/scripts/contentscript.js',
+		}));
+
+		// Unmute again.
+		await browser.tabs.update(tabId, { muted: false });
+
+		await tryUntilItWorks(() => browser.tabs.insertCSS(tabId, {
 			runAt: 'document_end',
 			file: '/assets/main.css',
-		});
-		browser.tabs.insertCSS(tabId, {
+		}));
+
+		await tryUntilItWorks(() => browser.tabs.insertCSS(tabId, {
 			runAt: 'document_end',
 			file: '/assets/waveform-playlist.css',
-		});
+		}));
 	}
 }
 

package-lock.json

@@ -1957,6 +1957,11 @@
         }
       }
     },
+    "delay": {
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/delay/-/delay-4.3.0.tgz",
+      "integrity": "sha512-Lwaf3zVFDMBop1yDuFZ19F9WyGcZcGacsbdlZtWjQmM50tOcMntm1njF/Nb/Vjij3KaSvCF+sEYGKrrjObu2NA=="
+    },
     "des.js": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/des.js/-/des.js-1.0.0.tgz",

package.json

@@ -15,6 +15,7 @@
     "webextension-toolbox": "latest"
   },
   "dependencies": {
+    "delay": "^4.3.0",
     "waveform-playlist": "^3.0.4"
   }
 }