Refactor ds-search-navbar so the <form> is only rendered when expanded

Pa11y/HTMLCS rule WCAG2AA H32.2 ("This form does not contain a submit
button") fires on every page because the navbar search renders a <form>
even while collapsed, and the icon control inside it is type="button"
(it has to be: in collapsed state its job is to expand the input, not
to submit). Functionally, Enter still submits the search via HTML5
implicit submission on a single-input form, so this is a false positive
in behavioural terms. The rule is, however, pointing at a real semantic
ambiguity: the icon button's role depends on whether the search is
collapsed or expanded.

Restructure the template so:
- when collapsed, only a single <button type="button"> is rendered
  (the magnifying-glass toggle). No form is in the DOM.
- when expanded, the full <form> is rendered with <input> and a real
  <button type="submit"> as the icon. Enter submits natively; clicking
  the icon submits natively.

The icon's role is now unambiguous in each state and Pa11y H32.2 no
longer reports the navbar form. The cypress e2e tests
(`cypress/e2e/search-navbar.cy.ts`) keep working because they query the
icon by `[data-test="header-search-icon"]`, which is set on both the
collapsed-state toggle and the expanded-state submit button.

The expand-on-collapse slide animation defined by `expandSearchInput`
is still applied to the input element while expanded; it is no longer
applied to the entry transition (the form simply appears). A follow-up
can re-introduce a `:enter`/`:leave` slide on the conditional form if
desired.

Fixes #5603

Author: bram-atmire

src/app/search-navbar/search-navbar.component.html

@@ -1,15 +1,24 @@
 <div [title]="'nav.search' | translate" (dsClickOutside)="collapse()">
   <div class="d-inline-block position-relative">
-    <form [formGroup]="searchForm" (ngSubmit)="onSubmit(searchForm.value)" autocomplete="on" class="d-flex">
-      <input #searchInput [@toggleAnimation]="isExpanded" [attr.aria-label]="('nav.search' | translate)" name="query"
-             formControlName="query" type="text" placeholder="{{searchExpanded ? ('nav.search' | translate) : ''}}"
-             class="d-inline-block bg-transparent position-absolute form-control dropdown-menu-end p1"
-             [class.display]="searchExpanded ? 'inline-block' : 'none'"
-             [tabIndex]="searchExpanded ? 0 : -1"
-             [attr.data-test]="'header-search-box' | dsBrowserOnly">
-      <button class="submit-icon btn btn-link btn-link-inline" [attr.aria-label]="'nav.search.button' | translate" type="button" (click)="searchExpanded ? onSubmit(searchForm.value) : expand()" [attr.data-test]="'header-search-icon' | dsBrowserOnly" tabindex="0" role="button">
+    @if (!searchExpanded) {
+      <button type="button" class="search-toggle btn btn-link btn-link-inline"
+              [attr.aria-label]="'nav.search.button' | translate"
+              (click)="expand()"
+              [attr.data-test]="'header-search-icon' | dsBrowserOnly">
         <em class="fas fa-search fa-lg fa-fw"></em>
       </button>
-    </form>
+    } @else {
+      <form [formGroup]="searchForm" (ngSubmit)="onSubmit(searchForm.value)" autocomplete="on" class="d-flex">
+        <input #searchInput [@toggleAnimation]="isExpanded" [attr.aria-label]="('nav.search' | translate)" name="query"
+               formControlName="query" type="text" placeholder="{{'nav.search' | translate}}"
+               class="d-inline-block bg-transparent position-absolute form-control dropdown-menu-end p1"
+               [attr.data-test]="'header-search-box' | dsBrowserOnly">
+        <button type="submit" class="submit-icon btn btn-link btn-link-inline"
+                [attr.aria-label]="'nav.search.button' | translate"
+                [attr.data-test]="'header-search-icon' | dsBrowserOnly">
+          <em class="fas fa-search fa-lg fa-fw"></em>
+        </button>
+      </form>
+    }
   </div>
 </div>

src/app/search-navbar/search-navbar.component.spec.ts

@@ -70,13 +70,24 @@ describe('SearchNavbarComponent', () => {
     expect(component).toBeTruthy();
   });
 
-  describe('when you click on search icon', () => {
+  describe('when collapsed', () => {
+    it('should render only the toggle <button> with no surrounding <form>', () => {
+      const form = fixture.debugElement.query(By.css('form'));
+      const toggle = fixture.debugElement.query(By.css('button.search-toggle'));
+      expect(form).toBeNull();
+      expect(toggle).not.toBeNull();
+      expect(toggle.nativeElement.tagName).toBe('BUTTON');
+      expect(toggle.nativeElement.getAttribute('type')).toBe('button');
+    });
+  });
+
+  describe('when you click on the search toggle', () => {
     beforeEach(fakeAsync(() => {
       spyOn(component, 'expand').and.callThrough();
       spyOn(component, 'onSubmit').and.callThrough();
       spyOn(router, 'navigate');
-      const searchIcon = fixture.debugElement.query(By.css('form .submit-icon'));
-      searchIcon.triggerEventHandler('click', {
+      const toggle = fixture.debugElement.query(By.css('button.search-toggle'));
+      toggle.triggerEventHandler('click', {
         preventDefault: () => {/**/
         },
       });
@@ -86,16 +97,22 @@ describe('SearchNavbarComponent', () => {
 
     it('input expands', () => {
       expect(component.expand).toHaveBeenCalled();
+      expect(component.searchExpanded).toBeTrue();
+    });
+
+    it('renders the form with a real submit button', () => {
+      const form = fixture.debugElement.query(By.css('form'));
+      const submit = fixture.debugElement.query(By.css('form button.submit-icon'));
+      expect(form).not.toBeNull();
+      expect(submit).not.toBeNull();
+      expect(submit.nativeElement.getAttribute('type')).toBe('submit');
     });
 
     describe('empty query', () => {
       describe('press submit button', () => {
         beforeEach(fakeAsync(() => {
-          const searchIcon = fixture.debugElement.query(By.css('form .submit-icon'));
-          searchIcon.triggerEventHandler('click', {
-            preventDefault: () => {/**/
-            },
-          });
+          const form = fixture.debugElement.query(By.css('form'));
+          form.triggerEventHandler('submit', null);
           tick();
           fixture.detectChanges();
         }));
@@ -117,17 +134,16 @@ describe('SearchNavbarComponent', () => {
         searchInput.nativeElement.dispatchEvent(new Event('input'));
         fixture.detectChanges();
       });
-      describe('press submit button', () => {
+      describe('press Enter on the input (native submit)', () => {
         beforeEach(fakeAsync(() => {
-          const searchIcon = fixture.debugElement.query(By.css('form .submit-icon'));
-          searchIcon.triggerEventHandler('click', null);
+          const form = fixture.debugElement.query(By.css('form'));
+          form.triggerEventHandler('submit', null);
           tick();
           fixture.detectChanges();
         }));
         it('to search page with query', async () => {
           const extras: NavigationExtras = { queryParams: { query: 'test' } };
           expect(component.onSubmit).toHaveBeenCalledWith({ query: 'test' });
-
           expect(router.navigate).toHaveBeenCalledWith(['search'], extras);
         });
       });

src/app/search-navbar/search-navbar.component.ts

@@ -1,4 +1,6 @@
 import {
+  AfterViewInit,
+  ChangeDetectorRef,
   Component,
   ElementRef,
   ViewChild,
@@ -17,7 +19,13 @@ import { BrowserOnlyPipe } from '../shared/utils/browser-only.pipe';
 import { ClickOutsideDirective } from '../shared/utils/click-outside.directive';
 
 /**
- * The search box in the header that expands on focus and collapses on focus out
+ * The search box in the header that expands on focus and collapses on focus out.
+ *
+ * When collapsed, only a single icon `<button>` is rendered (no form). The form, input
+ * and submit button are only rendered while the search bar is expanded; this avoids the
+ * Pa11y/HTMLCS rule WCAG2AA H32.2 ("This form does not contain a submit button"), which
+ * is otherwise reported on every page because the collapsed-state form had a
+ * `type="button"` icon control rather than a real submit button.
  */
 @Component({
   selector: 'ds-base-search-navbar',
@@ -32,57 +40,72 @@ import { ClickOutsideDirective } from '../shared/utils/click-outside.directive';
     TranslateModule,
   ],
 })
-export class SearchNavbarComponent {
+export class SearchNavbarComponent implements AfterViewInit {
 
   // The search form
   searchForm;
   // Whether or not the search bar is expanded, boolean for html ngIf, string for AngularAnimation state change
   searchExpanded = false;
   isExpanded = 'collapsed';
 
-  // Search input field
+  // Search input field. Only present once the form is rendered (`searchExpanded === true`).
   @ViewChild('searchInput') searchField: ElementRef;
 
-  constructor(private formBuilder: UntypedFormBuilder, private router: Router, private searchService: SearchService) {
+  constructor(
+    private formBuilder: UntypedFormBuilder,
+    private router: Router,
+    private searchService: SearchService,
+    private cdr: ChangeDetectorRef,
+  ) {
     this.searchForm = this.formBuilder.group(({
       query: '',
     }));
   }
 
+  ngAfterViewInit(): void {
+    // No-op; here so the @ViewChild reference is wired up after each render pass when
+    // the form is conditionally added/removed from the DOM.
+  }
+
   /**
-   * Expands search bar by angular animation, see expandSearchInput
+   * Expands the search bar and focuses the input on the next change-detection pass
+   * (the input only exists once `searchExpanded` is true).
    */
   expand() {
     this.searchExpanded = true;
     this.isExpanded = 'expanded';
+    // Force a synchronous render so `searchField` is populated, then focus it.
+    this.cdr.detectChanges();
     this.editSearch();
   }
 
   /**
-   * Collapses & blurs search bar by angular animation, see expandSearchInput
+   * Collapses & blurs the search bar. The form, input and submit button are removed
+   * from the DOM by the template's `@if (!searchExpanded)` branch.
    */
   collapse() {
-    this.searchField.nativeElement.blur();
+    this.searchField?.nativeElement?.blur();
     this.searchExpanded = false;
     this.isExpanded = 'collapsed';
   }
 
   /**
-   * Focuses on input search bar so search can be edited
+   * Focuses the input search bar so it can be edited.
    */
   editSearch(): void {
-    this.searchField.nativeElement.focus();
+    this.searchField?.nativeElement?.focus();
   }
 
   /**
-   * Submits the search (on enter or on search icon click)
+   * Submits the search. Triggered both by Enter on the input (native form submit) and
+   * by clicking the magnifying-glass icon (`<button type="submit">` inside the form).
    * @param data  Data for the searchForm, containing the search query
    */
   onSubmit(data: any) {
-    this.collapse();
     const queryParams = Object.assign({}, data);
     const linkToNavigateTo = [this.searchService.getSearchLink().replace('/', '')];
     this.searchForm.reset();
+    this.collapse();
 
     this.router.navigate(linkToNavigateTo, {
       queryParams: queryParams,