Add a system to create migrations for existing storage.

source/background.ts

@@ -4,12 +4,14 @@ import {
   getManifest,
   getNextQItem,
   getSettings,
+  migrate,
   newQItemID,
   QItem,
   QMessage,
   removeQItem,
   saveSettings,
-  updateBadge
+  updateBadge,
+  versionAsNumber
 } from '.';
 
 let timeoutID: number | null = null;
@@ -61,17 +63,28 @@ browser.runtime.onMessage.addListener(async (request: QMessage<unknown>) => {
 browser.runtime.onInstalled.addListener(async () => {
   const manifest = getManifest();
   const settings = await getSettings();
+  const versionGotUpdated =
+    versionAsNumber(manifest.version) > versionAsNumber(settings.latestVersion);
+
+  if (versionGotUpdated) {
+    // Set the previous sync storage data in the local storage as a backup.
+    const previous = await browser.storage.sync.get();
+    await browser.storage.local.clear();
+    await browser.storage.local.set(previous);
+
+    // Then migrate the sync storage data and update it.
+    const next = migrate(settings.latestVersion, previous);
+    next.latestVersion = manifest.version;
+    next.versionGotUpdated = versionGotUpdated;
+
+    await browser.storage.sync.clear();
+    await browser.storage.sync.set(next);
+  }
 
   // Open the options page when:
   // * The extension is first installed or is updated.
   // * In development, for convenience.
-  if (
-    manifest.version !== settings.latestVersion ||
-    manifest.nodeEnv === 'development'
-  ) {
-    settings.latestVersion = manifest.version;
-    settings.versionGotUpdated = true;
-    await saveSettings(settings);
+  if (versionGotUpdated || manifest.nodeEnv === 'development') {
     await openOptionsPage();
   }
 });

source/utilities/index.ts

@@ -73,5 +73,14 @@ export async function updateBadge(settings?: Settings): Promise<void> {
   ]);
 }
 
+/**
+ * Returns a version string as a number by removing the periods.
+ * @param version
+ */
+export function versionAsNumber(version: string): number {
+  return Number(version.replace(/\./g, ''));
+}
+
 export * from './components';
+export * from './migrations';
 export * from './settings';

source/utilities/migrations/2020-11-26.ts

@@ -0,0 +1,24 @@
+import {Migration, QItem} from '../..';
+
+export const migration_2020_11_26: Migration = {
+  date: new Date('2020-11-26T14:32:00.000Z'),
+  version: '0.1.7',
+  upgrade
+};
+
+/**
+ * This upgrades the sync settings to use 'qi<ID>'-named objects for QItems instead
+ * of them being in an array.
+ * Relevant commit: a668da05a179851b2a1117ef2d6aa9cef48d4964
+ */
+function upgrade(previous: Record<string, any>): Record<string, any> {
+  const items: QItem[] = previous.queue ?? [];
+  const next: Record<string, any> = previous;
+  delete next.queue;
+
+  for (const item of items) {
+    next['qi' + item.id.toString()] = item;
+  }
+
+  return next;
+}

source/utilities/migrations/index.ts

@@ -0,0 +1,30 @@
+import {log, versionAsNumber} from '../..';
+import {migration_2020_11_26} from './2020-11-26';
+
+export type Migration = {
+  date: Date;
+  version: string;
+  upgrade: (previous: Record<string, any>) => Record<string, any>;
+};
+
+const migrations: Migration[] = [migration_2020_11_26];
+
+export function migrate(
+  latestVersion: string,
+  previous: Record<string, any>
+): Record<string, any> {
+  let next = previous;
+
+  for (const migration of migrations) {
+    // If the saved version is >= the version from the migration, we've already
+    // handled it previously, so skip it.
+    if (versionAsNumber(latestVersion) >= versionAsNumber(migration.version)) {
+      continue;
+    }
+
+    log(`Running migration ${migration.date.toISOString()}`);
+    next = migration.upgrade(previous);
+  }
+
+  return next;
+}