background.js

@@ -33,6 +33,17 @@ async function generatePdf(data) {
   const url = URL.createObjectURL(blob);
   const name = (data.header && data.header.fullName) || 'Student';
   const filename = 'Study Load - ' + name + '.pdf';
-  await browser.downloads.download({ url, filename, saveAs: true });
-  setTimeout(() => URL.revokeObjectURL(url), 10000);
+  try {
+    const id = await browser.downloads.download({ url, filename, saveAs: true });
+    const onChanged = (delta) => {
+      if (delta.id === id && delta.state && (delta.state.current === 'complete' || delta.state.current === 'interrupted')) {
+        browser.downloads.onChanged.removeListener(onChanged);
+        URL.revokeObjectURL(url);
+      }
+    };
+    browser.downloads.onChanged.addListener(onChanged);
+  } catch (err) {
+    URL.revokeObjectURL(url);
+    throw err;
+  }
 }