website refactor

apps/website/lib/contracts/view-models/ViewModel.ts

@@ -0,0 +1,36 @@
+/**
+ * ViewModelBase contract
+ * 
+ * Base class for all ViewModels.
+ * 
+ * Based on VIEW_MODELS.md:
+ * - Client-only classes
+ * - Fully prepared UI state
+ * - Never serialized
+ * - Never passed to Templates
+ * - Compose Display Objects for reusable formatting
+ * - Expose UI-specific computed properties
+ * 
+ * Based on WEBSITE_CONTRACT.md:
+ * - ViewModels are client-only
+ * - Must not expose methods that return Page DTO or API DTO
+ * 
+ * Architecture Flow:
+ * 1. PageQuery returns Page DTO (server)
+ * 2. Presenter transforms Page DTO → ViewModel (client)
+ * 3. Presenter transforms ViewModel → ViewData (client)
+ * 4. Template receives ViewData only
+ * 
+ * ViewModels provide UI state and helpers.
+ * Presenters handle the transformation to ViewData.
+ */
+
+export abstract class ViewModel {
+  /**
+   * Optional: Validate the ViewModel state
+   * 
+   * Can be used to ensure the ViewModel is in a valid state
+   * before a Presenter converts it to ViewData.
+   */
+  validate?(): boolean;
+}