feat: Added "Whats New" indicator to Preferences button (#2107)

packages/ui-services/src/Changelog/ChangelogService.ts

@@ -1,7 +1,7 @@
 import { Environment } from '@standardnotes/models'
 import { StorageServiceInterface, StorageKey } from '@standardnotes/services'
 import { Changelog, ChangelogVersion } from './Changelog'
-import { ChangelogServiceInterface } from './ChangelogServiceInterface'
+import { ChangelogLastReadVersionListener, ChangelogServiceInterface } from './ChangelogServiceInterface'
 import { LegacyWebToDesktopVersionMapping } from './LegacyDesktopMapping'
 import { LegacyWebToMobileVersionMapping } from './LegacyMobileMapping'
 
@@ -10,9 +10,18 @@ const DesktopDownloadsUrlBase = 'https://github.com/standardnotes/app/releases/t
 
 export class ChangelogService implements ChangelogServiceInterface {
   private changeLog?: Changelog
+  private lastReadChangeListeners: ChangelogLastReadVersionListener[] = []
 
   constructor(private environment: Environment, private diskService: StorageServiceInterface) {}
 
+  public addLastReadChangeListener(listener: ChangelogLastReadVersionListener) {
+    this.lastReadChangeListeners.push(listener)
+
+    return () => {
+      this.lastReadChangeListeners = this.lastReadChangeListeners.filter((l) => l !== listener)
+    }
+  }
+
   private async performDownloadChangelog(): Promise<Changelog> {
     const response = await fetch(WebChangelogUrl)
     const changelog = await response.text()
@@ -47,7 +56,11 @@ export class ChangelogService implements ChangelogServiceInterface {
       return
     }
 
-    this.diskService.setValue(StorageKey.LastReadChangelogVersion, this.changeLog.versions[0].version)
+    const version = this.changeLog.versions[0].version
+    this.diskService.setValue(StorageKey.LastReadChangelogVersion, version)
+    if (version) {
+      this.lastReadChangeListeners.forEach((listener) => listener(version))
+    }
   }
 
   public getLastReadVersion(): string | undefined {

packages/ui-services/src/Changelog/ChangelogServiceInterface.ts

@@ -1,6 +1,9 @@
 import { Changelog, ChangelogVersion } from './Changelog'
 
+export type ChangelogLastReadVersionListener = (version: string) => void
+
 export interface ChangelogServiceInterface {
+  addLastReadChangeListener(listener: ChangelogLastReadVersionListener): () => void
   getChangelog(): Promise<Changelog>
   getVersions(): Promise<ChangelogVersion[]>
   getDesktopDownloadsUrl(version: string): string