Merge pull request #12872 from lunarway/feature/techdocs-scroll

Add navigation scroll to techdocs

plugins/techdocs/src/reader/components/TechDocsReaderPageContent/dom.tsx

@@ -41,6 +41,7 @@ import {
   rewriteDocLinks,
   simplifyMkdocsFooter,
   scrollIntoAnchor,
+  scrollIntoNavigation,
   transform as transformer,
   copyToClipboard,
   useSanitizerTransformer,
@@ -166,6 +167,7 @@ export const useTechDocsReaderDom = (
     async (transformedElement: Element) =>
       transformer(transformedElement, [
         scrollIntoAnchor(),
+        scrollIntoNavigation(),
         copyToClipboard(theme),
         addLinkClickListener({
           baseUrl: window.location.origin,

plugins/techdocs/src/reader/transformers/index.ts

@@ -26,4 +26,5 @@ export * from './removeMkdocsHeader';
 export * from './simplifyMkdocsFooter';
 export * from './onCssReady';
 export * from './scrollIntoAnchor';
+export * from './scrollIntoNavigation';
 export * from './transformer';

plugins/techdocs/src/reader/transformers/scrollIntoNavigation.test.ts

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { scrollIntoNavigation } from '.';
+import { createTestShadowDom, FIXTURES } from '../../test-utils';
+
+jest.useFakeTimers();
+
+describe('scrollIntoNavigation', () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('scroll to active navigation item', async () => {
+    await createTestShadowDom(FIXTURES.FIXTURE_STANDARD_PAGE, {
+      preTransformers: [],
+      postTransformers: [scrollIntoNavigation()],
+    });
+
+    // jsdom does not implement scrollIntoView so we attach a function to the
+    // prototype to be able to test the expected behaviour.
+    const scrollNavIntoView = jest.fn();
+    window.HTMLElement.prototype.scrollIntoView = scrollNavIntoView;
+
+    jest.advanceTimersByTime(200);
+
+    expect(scrollNavIntoView).toHaveBeenCalledWith();
+  });
+
+  it('expand active navigation items', async () => {
+    const shadowDom = await createTestShadowDom(
+      FIXTURES.FIXTURE_STANDARD_PAGE,
+      {
+        preTransformers: [],
+        postTransformers: [scrollIntoNavigation()],
+      },
+    );
+
+    // jsdom does not implement scrollIntoView so we attach an empty function to
+    // support the behaviour.
+    window.HTMLElement.prototype.scrollIntoView = () => {};
+
+    const click = jest.fn();
+    shadowDom.addEventListener('click', click);
+
+    jest.advanceTimersByTime(200);
+
+    expect(click).toHaveBeenCalled();
+  });
+
+  it('does not expand already expanded active navigation items', async () => {
+    const shadowDom = await createTestShadowDom(
+      FIXTURES.FIXTURE_STANDARD_PAGE_EXPANDED_NAVIGATION,
+      {
+        preTransformers: [],
+        postTransformers: [scrollIntoNavigation()],
+      },
+    );
+
+    // jsdom does not implement scrollIntoView so we attach an empty function to
+    // support the behaviour.
+    window.HTMLElement.prototype.scrollIntoView = () => {};
+
+    const click = jest.fn();
+    shadowDom.addEventListener('click', click);
+
+    jest.advanceTimersByTime(200);
+
+    expect(click).not.toHaveBeenCalled();
+  });
+});

plugins/techdocs/src/reader/transformers/scrollIntoNavigation.ts

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import type { Transformer } from './transformer';
+
+export const scrollIntoNavigation = (): Transformer => {
+  return dom => {
+    setTimeout(() => {
+      const activeNavItems = dom?.querySelectorAll(`li.md-nav__item--active`);
+      if (activeNavItems.length !== 0) {
+        // expand all navigation items that are active
+        activeNavItems.forEach(activeNavItem => {
+          const checkbox = activeNavItem?.querySelector('input');
+          if (!checkbox?.checked) {
+            checkbox?.click();
+          }
+        });
+
+        const lastItem = activeNavItems[activeNavItems.length - 1];
+        lastItem.scrollIntoView();
+      }
+    }, 200);
+    return dom;
+  };
+};

plugins/techdocs/src/test-utils/index.ts

@@ -15,9 +15,11 @@
  */
 
 import FIXTURE_STANDARD_PAGE from './fixtures/mkdocs-index';
+import FIXTURE_STANDARD_PAGE_EXPANDED_NAVIGATION from './fixtures/mkdocs-expanded-index';
 
 export const FIXTURES = {
   FIXTURE_STANDARD_PAGE,
+  FIXTURE_STANDARD_PAGE_EXPANDED_NAVIGATION,
 };
 
 export * from './shadowDom';