fix(desktop): preserve restored zoom state

apps/desktop/src/store/zoom.test.ts

@@ -0,0 +1,76 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+const desktopWindow = window as unknown as { hermesDesktop?: Window['hermesDesktop'] }
+const initialHermesDesktop = desktopWindow.hermesDesktop
+
+type ZoomBridge = NonNullable<Window['hermesDesktop']['zoom']>
+type ZoomPayload = Awaited<ReturnType<ZoomBridge['get']>>
+
+function installZoomBridge(zoom: ZoomBridge): void {
+  desktopWindow.hermesDesktop = { zoom } as unknown as Window['hermesDesktop']
+}
+
+beforeEach(() => {
+  vi.resetModules()
+})
+
+afterEach(() => {
+  if (initialHermesDesktop) {
+    desktopWindow.hermesDesktop = initialHermesDesktop
+  } else {
+    delete desktopWindow.hermesDesktop
+  }
+})
+
+describe('zoom state sync', () => {
+  it('uses the initial read when no newer change has arrived', async () => {
+    const zoom: ZoomBridge = {
+      get: vi.fn().mockResolvedValue({ level: 1, percent: 125 }),
+      onChanged: vi.fn(() => vi.fn()),
+      setPercent: vi.fn()
+    }
+
+    installZoomBridge(zoom)
+
+    const { $zoomPercent } = await import('./zoom')
+
+    expect($zoomPercent.get()).toBe(125)
+  })
+
+  it('does not let a stale initial read overwrite a newer zoom event', async () => {
+    const callOrder: string[] = []
+    let emitChanged: ((payload: ZoomPayload) => void) | undefined
+    let resolveInitialRead: ((payload: ZoomPayload) => void) | undefined
+
+    const initialRead = new Promise<ZoomPayload>(resolve => {
+      resolveInitialRead = resolve
+    })
+
+    const zoom: ZoomBridge = {
+      get: vi.fn(() => {
+        callOrder.push('get')
+
+        return initialRead
+      }),
+      onChanged: vi.fn(callback => {
+        callOrder.push('subscribe')
+        emitChanged = callback
+
+        return vi.fn()
+      }),
+      setPercent: vi.fn()
+    }
+
+    installZoomBridge(zoom)
+
+    const { $zoomPercent } = await import('./zoom')
+
+    expect(callOrder).toEqual(['subscribe', 'get'])
+    emitChanged?.({ level: 1, percent: 125 })
+    resolveInitialRead?.({ level: 0, percent: 100 })
+    await initialRead
+    await Promise.resolve()
+
+    expect($zoomPercent.get()).toBe(125)
+  })
+})

apps/desktop/src/store/zoom.ts

@@ -19,6 +19,17 @@ export function setZoomPercent(percent: number): void {
 }
 
 if (typeof window !== 'undefined' && window.hermesDesktop?.zoom) {
-  void window.hermesDesktop.zoom.get().then(({ percent }) => $zoomPercent.set(percent))
-  window.hermesDesktop.zoom.onChanged(({ percent }) => $zoomPercent.set(percent))
+  const zoom = window.hermesDesktop.zoom
+  let receivedZoomChange = false
+
+  zoom.onChanged(({ percent }) => {
+    receivedZoomChange = true
+    $zoomPercent.set(percent)
+  })
+
+  void zoom.get().then(({ percent }) => {
+    if (!receivedZoomChange) {
+      $zoomPercent.set(percent)
+    }
+  })
 }