add hasHeaderBanner$ API to chrome (#111248) (#111391)

* add hasHeaderBanner$ API to chrome

* update generated doc

Co-authored-by: Pierre Gayvallet <pierre.gayvallet@gmail.com>

docs/development/core/public/kibana-plugin-core-public.chromestart.hasheaderbanner_.md

@@ -0,0 +1,17 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-core-public](./kibana-plugin-core-public.md) &gt; [ChromeStart](./kibana-plugin-core-public.chromestart.md) &gt; [hasHeaderBanner$](./kibana-plugin-core-public.chromestart.hasheaderbanner_.md)
+
+## ChromeStart.hasHeaderBanner$() method
+
+Get an observable of the current header banner presence state.
+
+<b>Signature:</b>
+
+```typescript
+hasHeaderBanner$(): Observable<boolean>;
+```
+<b>Returns:</b>
+
+`Observable<boolean>`
+

docs/development/core/public/kibana-plugin-core-public.chromestart.md

@@ -57,6 +57,7 @@ core.chrome.setHelpExtension(elem => {
 |  [getHelpExtension$()](./kibana-plugin-core-public.chromestart.gethelpextension_.md) | Get an observable of the current custom help conttent |
 |  [getIsNavDrawerLocked$()](./kibana-plugin-core-public.chromestart.getisnavdrawerlocked_.md) | Get an observable of the current locked state of the nav drawer. |
 |  [getIsVisible$()](./kibana-plugin-core-public.chromestart.getisvisible_.md) | Get an observable of the current visibility state of the chrome. |
+|  [hasHeaderBanner$()](./kibana-plugin-core-public.chromestart.hasheaderbanner_.md) | Get an observable of the current header banner presence state. |
 |  [setBadge(badge)](./kibana-plugin-core-public.chromestart.setbadge.md) | Override the current badge |
 |  [setBreadcrumbs(newBreadcrumbs)](./kibana-plugin-core-public.chromestart.setbreadcrumbs.md) | Override the current set of breadcrumbs |
 |  [setBreadcrumbsAppendExtension(breadcrumbsAppendExtension)](./kibana-plugin-core-public.chromestart.setbreadcrumbsappendextension.md) | Mount an element next to the last breadcrumb |

src/core/public/chrome/chrome_service.mock.ts

@@ -55,6 +55,7 @@ const createStartContractMock = () => {
     getCustomNavLink$: jest.fn(),
     setCustomNavLink: jest.fn(),
     setHeaderBanner: jest.fn(),
+    hasHeaderBanner$: jest.fn(),
     getBodyClasses$: jest.fn(),
   };
   startContract.navLinks.getAll.mockReturnValue([]);
@@ -66,6 +67,7 @@ const createStartContractMock = () => {
   startContract.getHelpExtension$.mockReturnValue(new BehaviorSubject(undefined));
   startContract.getIsNavDrawerLocked$.mockReturnValue(new BehaviorSubject(false));
   startContract.getBodyClasses$.mockReturnValue(new BehaviorSubject([]));
+  startContract.hasHeaderBanner$.mockReturnValue(new BehaviorSubject(false));
   return startContract;
 };
 

src/core/public/chrome/chrome_service.test.ts

@@ -390,6 +390,19 @@ describe('start', () => {
     });
   });
 
+  describe('header banner', () => {
+    it('updates/emits the state of the header banner', async () => {
+      const { chrome, service } = await start();
+      const promise = chrome.hasHeaderBanner$().pipe(toArray()).toPromise();
+
+      chrome.setHeaderBanner({ content: () => () => undefined });
+      chrome.setHeaderBanner(undefined);
+      service.stop();
+
+      await expect(promise).resolves.toEqual([false, true, false]);
+    });
+  });
+
   describe('erase chrome fields', () => {
     it('while switching an app', async () => {
       const startDeps = defaultStartDeps([new FakeApp('alpha')]);

src/core/public/chrome/chrome_service.tsx

@@ -273,6 +273,13 @@ export class ChromeService {
         headerBanner$.next(headerBanner);
       },
 
+      hasHeaderBanner$: () => {
+        return headerBanner$.pipe(
+          takeUntil(this.stop$),
+          map((banner) => Boolean(banner))
+        );
+      },
+
       getBodyClasses$: () => bodyClasses$.pipe(takeUntil(this.stop$)),
     };
   }

src/core/public/chrome/types.ts

@@ -168,6 +168,11 @@ export interface ChromeStart {
    * @remarks Using `undefined` when invoking this API will remove the banner.
    */
   setHeaderBanner(headerBanner?: ChromeUserBanner): void;
+
+  /**
+   * Get an observable of the current header banner presence state.
+   */
+  hasHeaderBanner$(): Observable<boolean>;
 }
 
 /** @internal */

src/core/public/public.api.md

@@ -356,6 +356,7 @@ export interface ChromeStart {
     getHelpExtension$(): Observable<ChromeHelpExtension | undefined>;
     getIsNavDrawerLocked$(): Observable<boolean>;
     getIsVisible$(): Observable<boolean>;
+    hasHeaderBanner$(): Observable<boolean>;
     navControls: ChromeNavControls;
     navLinks: ChromeNavLinks;
     recentlyAccessed: ChromeRecentlyAccessed;