docs: add copy buttons to markdown code blocks

docs/src/app/shared/doc-viewer/code-block-copy-button/code-block-copy-button.ts

@@ -0,0 +1,44 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import {Component, inject} from '@angular/core';
+import {MatIconButton} from '@angular/material/button';
+import {MatIcon} from '@angular/material/icon';
+import {MatSnackBar} from '@angular/material/snack-bar';
+import {MatTooltip} from '@angular/material/tooltip';
+import {Clipboard} from '@angular/cdk/clipboard';
+
+/** Icon button that copies the contents of a code block to the clipboard. */
+@Component({
+  selector: 'code-block-copy-button',
+  imports: [MatIconButton, MatIcon, MatTooltip],
+  template: `
+    <button
+      mat-icon-button
+      aria-label="Copy code"
+      matTooltip="Copy code to the clipboard"
+      (click)="copy()">
+      <mat-icon>content_copy</mat-icon>
+    </button>
+  `,
+})
+export class CodeBlockCopyButton {
+  private _clipboard = inject(Clipboard);
+  private _snackbar = inject(MatSnackBar);
+
+  /** Code snippet that will be copied. */
+  code = '';
+
+  copy(): void {
+    const message = this._clipboard.copy(this.code)
+      ? 'Copied code snippet'
+      : 'Failed to copy code snippet';
+
+    this._snackbar.open(message, undefined, {duration: 2500});
+  }
+}

docs/src/app/shared/doc-viewer/doc-viewer.spec.ts

@@ -209,6 +209,28 @@ describe('DocViewer', () => {
     expect(clipboardSpy.copy).toHaveBeenCalled();
   });
 
+  it('should show copy icon button for code blocks', () => {
+    const fixture = TestBed.createComponent(DocViewerTestComponent);
+    fixture.componentInstance.documentUrl = `http://material.angular.io/doc-with-code-block.html`;
+    fixture.detectChanges();
+
+    const url = fixture.componentInstance.documentUrl;
+    http.expectOne(url).flush(FAKE_DOCS[url]);
+
+    const docViewer = fixture.debugElement.query(By.directive(DocViewer));
+    expect(docViewer).not.toBeNull();
+
+    // Query all copy buttons within code blocks
+    const iconButtons = fixture.debugElement.queryAll(By.directive(MatIconButton));
+    // At least one icon button for copying code should exist
+    expect(iconButtons.length).toBeGreaterThan(0);
+
+    // Click on the first icon button to trigger copying the code
+    iconButtons[0].nativeNode.dispatchEvent(new MouseEvent('click'));
+    fixture.detectChanges();
+    expect(clipboardSpy.copy).toHaveBeenCalledWith('const example = "test code";');
+  });
+
   // TODO(mmalerba): Add test that example-viewer is instantiated.
 });
 
@@ -261,6 +283,10 @@ const FAKE_DOCS: {[key: string]: string} = {
         data-docs-api-module-import-button="import {MatIconModule} from '@angular/material/icon';">
       </div>
     </div>`,
+  'http://material.angular.io/doc-with-code-block.html': `
+    <div class="docs-markdown">
+      <pre><code>const example = "test code";</code></pre>
+    </div>`,
 };
 
 @Component({

docs/src/app/shared/doc-viewer/doc-viewer.ts

@@ -40,6 +40,7 @@ import {HeaderLink} from './header-link';
 import {DeprecatedFieldComponent} from './deprecated-tooltip';
 import {ModuleImportCopyButton} from './module-import-copy-button';
 import {AngularAriaBanner} from './angular-aria-banner/angular-aria-banner';
+import {CodeBlockCopyButton} from './code-block-copy-button/code-block-copy-button';
 
 @Service()
 class DocFetcher {
@@ -167,6 +168,9 @@ export class DocViewer implements OnDestroy {
     // Create icon buttons to copy module import
     this._createCopyIconForModule();
 
+    // Create icon buttons to copy code blocks
+    this._createCopyButtonsForCodeBlocks();
+
     // Resolving and creating components dynamically in Angular happens synchronously, but since
     // we want to emit the output if the components are actually rendered completely, we wait
     // until the Angular zone becomes stable.
@@ -306,4 +310,31 @@ export class DocViewer implements OnDestroy {
 
     this._portalHosts.push(portalHost);
   }
+
+  /** Adds a button to copy the code to every code block in the document. */
+  private _createCopyButtonsForCodeBlocks() {
+    // Query all <pre> tags that contain <code> elements (markdown code blocks)
+    const codeBlockElements = this._elementRef.nativeElement.querySelectorAll(
+      '.docs-markdown pre:has(code)',
+    );
+
+    [...codeBlockElements].forEach((element: HTMLElement) => {
+      // Extract the text content from the code block
+      const codeElement = element.querySelector('code');
+      const codeSnippet = codeElement?.textContent || '';
+
+      const elementPortalOutlet = new DomPortalOutlet(element, this._appRef, this._injector);
+      const codeBlockCopyButtonPortal = new ComponentPortal(
+        CodeBlockCopyButton,
+        this._viewContainerRef,
+      );
+      const codeBlockCopyButtonOutlet = elementPortalOutlet.attach(codeBlockCopyButtonPortal);
+
+      if (codeSnippet) {
+        codeBlockCopyButtonOutlet.instance.code = codeSnippet;
+      }
+
+      this._portalHosts.push(elementPortalOutlet);
+    });
+  }
 }

docs/src/styles/_markdown.scss

@@ -76,12 +76,19 @@
 
       border: solid 1px var(--mat-sys-outline-variant);
       border-radius: 12px;
+      position: relative;
 
       code {
         background: transparent;
         padding: 0;
         font-size: 100%;
       }
+
+      code-block-copy-button {
+        position: absolute;
+        top: 5px;
+        right: 5px;
+      }
     }
 
     code {