refactor: Centralize template render type assertion (#2538)

src/card-controller/actions/actions-manager.ts

@@ -187,15 +187,14 @@ export class ActionsManager implements ActionsExecutor {
     triggerData?: TriggerData,
   ): ActionPrepareCallback {
     // Render against the state (incl. HASS) as it is *when the action runs* --
-    // fixed trigger context, fresh card/HASS state per step. The one cast lives
+    // fixed trigger context, fresh card/HASS state per step.
-    // here as renderRecursively returns `unknown`.
     return <T>(value: T): T => {
       const hass = this._api.getHASSManager().getHASS();
       return hass
-        ? (renderer.renderRecursively(hass, value, {
+        ? renderer.renderRecursivelyAsType(hass, value, {
             conditionState: this._api.getConditionStateManager().getState(),
             triggerData,
-          }) as T)
+          })
         : value;
     };
   }

src/card-controller/templates/index.ts

@@ -31,6 +31,17 @@ export class TemplateRenderer {
     );
   };
 
+  // Structure-preserving variant of `renderRecursively`: arrays, records, and
+  // primitives keep their shape (only string leaves are rendered), so the
+  // caller's type is asserted back unchanged. Callers whose template renders to
+  // a *different* type than its input (e.g. a string that yields a boolean)
+  // must use `renderRecursively` and narrow the `unknown` result at runtime.
+  public renderRecursivelyAsType = <T>(
+    hass: HomeAssistant,
+    data: T,
+    options?: TemplateRenderOptions,
+  ): T => this.renderRecursively(hass, data, options) as T;
+
   private _generateTemplateContext(
     options?: TemplateRenderOptions,
   ): TemplateContext | undefined {

src/components/elements.ts

@@ -136,9 +136,13 @@ export class AdvancedCameraCardElementsCore extends LitElement {
       return;
     }
 
-    const elements = this._templateRenderer.renderRecursively(this.hass, this.elements, {
+    const elements = this._templateRenderer.renderRecursivelyAsType(
-      conditionState: this.conditionStateManager?.getState(),
+      this.hass,
-    }) as PictureElements | undefined;
+      this.elements,
+      {
+        conditionState: this.conditionStateManager?.getState(),
+      },
+    );
 
     // Condition state changes won't change the actual rendered config unless
     // `elements` has a template, which is more likely does not. Avoid updating

tests/card-controller/actions/actions-manager.test.ts

@@ -337,7 +337,7 @@ describe('ActionsManager', () => {
       const action = createLogAction('{{ acc.camera }}');
 
       const templateRenderer = mock<TemplateRenderer>();
-      templateRenderer.renderRecursively.mockReturnValue(action);
+      templateRenderer.renderRecursivelyAsType.mockReturnValue(action);
 
       const api = createAPI();
       const hass = createHASS();
@@ -360,7 +360,7 @@ describe('ActionsManager', () => {
 
       await manager.executeActions({ actions: action, config, triggerData });
 
-      expect(templateRenderer.renderRecursively).toBeCalledWith(hass, action, {
+      expect(templateRenderer.renderRecursivelyAsType).toBeCalledWith(hass, action, {
         conditionState,
         triggerData,
       });
@@ -377,7 +377,7 @@ describe('ActionsManager', () => {
       });
 
       const templateRenderer = mock<TemplateRenderer>();
-      templateRenderer.renderRecursively.mockReturnValue(allowedAction);
+      templateRenderer.renderRecursivelyAsType.mockReturnValue(allowedAction);
 
       const api = createAPI();
       vi.mocked(api.getHASSManager().getHASS).mockReturnValue(createHASS());
@@ -399,7 +399,7 @@ describe('ActionsManager', () => {
 
       const templateRenderer = mock<TemplateRenderer>();
       // Identity render -- assert on the render *inputs*, not a swapped output.
-      templateRenderer.renderRecursively.mockImplementation((_hass, data) => data);
+      templateRenderer.renderRecursivelyAsType.mockImplementation((_hass, data) => data);
 
       const api = createAPI();
       vi.mocked(api.getHASSManager().getHASS).mockReturnValue(createHASS());
@@ -422,13 +422,13 @@ describe('ActionsManager', () => {
 
       // Each action renders with the state as it is at its turn: the second
       // sees the camera the first action set.
-      expect(templateRenderer.renderRecursively).toHaveBeenNthCalledWith(
+      expect(templateRenderer.renderRecursivelyAsType).toHaveBeenNthCalledWith(
         1,
         expect.anything(),
         expect.anything(),
         expect.objectContaining({ conditionState: { camera: 'first' } }),
       );
-      expect(templateRenderer.renderRecursively).toHaveBeenNthCalledWith(
+      expect(templateRenderer.renderRecursivelyAsType).toHaveBeenNthCalledWith(
         2,
         expect.anything(),
         expect.anything(),
@@ -440,7 +440,7 @@ describe('ActionsManager', () => {
       const ran: string[] = [];
 
       const templateRenderer = mock<TemplateRenderer>();
-      templateRenderer.renderRecursively.mockImplementation((_hass, data) => data);
+      templateRenderer.renderRecursivelyAsType.mockImplementation((_hass, data) => data);
 
       const api = createAPI();
       // No HASS for the first action's render; HASS thereafter.
@@ -464,14 +464,14 @@ describe('ActionsManager', () => {
       // Both actions ran; only the second was rendered -- the first saw no
       // HASS, so HASS is read per action rather than captured once.
       expect(ran).toEqual(['one', 'two']);
-      expect(templateRenderer.renderRecursively).toBeCalledTimes(1);
+      expect(templateRenderer.renderRecursivelyAsType).toBeCalledTimes(1);
     });
 
     it('should abort the remaining actions when one fails to render', async () => {
       const ran: string[] = [];
 
       const templateRenderer = mock<TemplateRenderer>();
-      templateRenderer.renderRecursively
+      templateRenderer.renderRecursivelyAsType
         .mockImplementationOnce((_hass, data) => data)
         .mockImplementationOnce(() => {
           throw new Error('bad template');

tests/card-controller/templates/index.test.ts

@@ -178,4 +178,18 @@ describe('TemplateRenderer', () => {
       expect(result).toBe('Value:');
     });
   });
+
+  describe('renderRecursivelyAsType', () => {
+    it('should render in place while preserving the input structure', () => {
+      const renderer = new TemplateRenderer();
+      const hass = createHASS();
+
+      const result = renderer.renderRecursivelyAsType(
+        hass,
+        { camera: '{{ acc.camera }}', static: 'value' },
+        { conditionState: { camera: 'camera.office' } },
+      );
+      expect(result).toEqual({ camera: 'camera.office', static: 'value' });
+    });
+  });
 });