app-react: new API for consuming nav items that detects page extensions

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/app-react/src/blueprints/NavContentBlueprint.test.tsx

@@ -14,12 +14,26 @@
  * limitations under the License.
  */
 
-import { createRouteRef } from '@backstage/frontend-plugin-api';
-import { NavContentBlueprint } from './NavContentBlueprint';
+import { AppNode, createRouteRef } from '@backstage/frontend-plugin-api';
+import { NavContentBlueprint, NavItem, NavItems } from './NavContentBlueprint';
 import { createExtensionTester } from '@backstage/frontend-test-utils';
 
 const routeRef = createRouteRef();
 
+function mockNode(id: string): AppNode {
+  return { spec: { id } } as AppNode;
+}
+
+function mockNavItems(items: NavItem[]): NavItems {
+  return {
+    take: () => undefined,
+    rest: () => items,
+    clone() {
+      return mockNavItems(items);
+    },
+  };
+}
+
 describe('NavContentBlueprint', () => {
   it('should create an extension with sensible defaults', () => {
     const extension = NavContentBlueprint.make({
@@ -52,22 +66,7 @@ describe('NavContentBlueprint', () => {
     `);
   });
 
-  it('should return a valid component', () => {
-    const extension = NavContentBlueprint.make({
-      name: 'test',
-      params: {
-        component: () => <div>Nav content</div>,
-      },
-    });
-
-    const tester = createExtensionTester(extension);
-
-    expect(
-      tester.get(NavContentBlueprint.dataRefs.component)({ items: [] }),
-    ).toEqual(<div>Nav content</div>);
-  });
-
-  it('should return a valid component with items', () => {
+  it('should return a valid component with legacy items', () => {
     const extension = NavContentBlueprint.make({
       name: 'test',
       params: {
@@ -88,6 +87,7 @@ describe('NavContentBlueprint', () => {
 
     expect(
       tester.get(NavContentBlueprint.dataRefs.component)({
+        navItems: mockNavItems([]),
         items: [
           {
             to: '/',
@@ -109,4 +109,68 @@ describe('NavContentBlueprint', () => {
       </div>,
     );
   });
+
+  it('should return a valid component with navItems', () => {
+    const items: NavItem[] = [
+      {
+        node: mockNode('page:home'),
+        href: '/',
+        title: 'Home',
+        icon: <span>home</span>,
+        routeRef,
+      },
+      {
+        node: mockNode('page:catalog'),
+        href: '/catalog',
+        title: 'Catalog',
+        icon: <span>catalog</span>,
+        routeRef,
+      },
+      {
+        node: mockNode('page:docs'),
+        href: '/docs',
+        title: 'Docs',
+        icon: <span>docs</span>,
+        routeRef,
+      },
+    ];
+
+    const extension = NavContentBlueprint.make({
+      name: 'test',
+      params: {
+        component: ({ navItems }) => (
+          <div>
+            {navItems.rest().map(item => (
+              <a key={item.node.spec.id} href={item.href}>
+                {item.title}
+              </a>
+            ))}
+          </div>
+        ),
+      },
+    });
+
+    const tester = createExtensionTester(extension);
+
+    expect(
+      tester.get(NavContentBlueprint.dataRefs.component)({
+        navItems: mockNavItems(items),
+        items: [],
+      }),
+    ).toEqual(
+      <div>
+        {[
+          <a key="page:home" href="/">
+            Home
+          </a>,
+          <a key="page:catalog" href="/catalog">
+            Catalog
+          </a>,
+          <a key="page:docs" href="/docs">
+            Docs
+          </a>,
+        ]}
+      </div>,
+    );
+  });
 });

plugins/app-react/src/blueprints/NavContentBlueprint.ts

@@ -14,12 +14,50 @@
  * limitations under the License.
  */
 
-import { IconComponent, RouteRef } from '@backstage/frontend-plugin-api';
+import {
+  AppNode,
+  IconComponent,
+  IconElement,
+  RouteRef,
+} from '@backstage/frontend-plugin-api';
 import {
   createExtensionBlueprint,
   createExtensionDataRef,
 } from '@backstage/frontend-plugin-api';
 
+/**
+ * A navigation item auto-discovered from a page extension in the app.
+ *
+ * @public
+ */
+export interface NavItem {
+  /** The app node of the page extension that this nav item points to */
+  node: AppNode;
+  /** The resolved route path */
+  href: string;
+  /** The display title */
+  title: string;
+  /** The display icon */
+  icon: IconElement;
+  /** The route ref of the source page */
+  routeRef: RouteRef;
+}
+
+/**
+ * A collection of nav items that supports picking specific items by ID
+ * and retrieving whatever remains. Created fresh for each render.
+ *
+ * @public
+ */
+export interface NavItems {
+  /** Take an item by extension ID, removing it from the collection. */
+  take(id: string): NavItem | undefined;
+  /** All items not yet taken. */
+  rest(): NavItem[];
+  /** Create a copy of the collection preserving the current taken state. */
+  clone(): NavItems;
+}
+
 /**
  * The props for the {@link NavContentComponent}.
  *
@@ -27,20 +65,21 @@ import {
  */
 export interface NavContentComponentProps {
   /**
-   * The nav items available to the component. These are all the items created
-   * with the {@link @backstage/frontend-plugin-api#NavItemBlueprint} in the app.
+   * Nav items auto-discovered from page extensions, with take/rest semantics
+   * for placing specific items in specific positions.
+   */
+  navItems: NavItems;
+
+  /**
+   * Flat list of nav items for simple rendering. Use `navItems` for more
+   * control over item placement.
    *
-   * In addition to the original properties from the nav items, these also
-   * include a resolved route path as `to`, and duplicated `title` as `text` to
-   * simplify rendering.
+   * @deprecated Use `navItems` instead.
    */
   items: Array<{
-    // Original props from nav items
     icon: IconComponent;
     title: string;
     routeRef: RouteRef<undefined>;
-
-    // Additional props to simplify item rendering
     to: string;
     text: string;
   }>;

plugins/app-react/src/blueprints/index.ts

@@ -20,6 +20,8 @@ export { NavContentBlueprint } from './NavContentBlueprint';
 export type {
   NavContentComponent,
   NavContentComponentProps,
+  NavItem,
+  NavItems,
 } from './NavContentBlueprint';
 export { RouterBlueprint } from './RouterBlueprint';
 export { SignInPageBlueprint } from './SignInPageBlueprint';