fix(aio): remove links from sub-menu toggles (#21695)

Navigating to a document while trying to expand or collapse a sub-menu
is undesirable and confusing. All sub-menu toggles should have no other
effect than expanding/collapsing the corresponding sub-menu.

PR Close #21695

aio/content/navigation.json

@@ -74,7 +74,6 @@
     },
 
     {
-      "url": "tutorial",
       "title": "Tutorial",
       "tooltip": "The Tour of Heroes tutorial takes you through the steps of creating an Angular application in TypeScript.",
       "children": [
@@ -122,7 +121,6 @@
     },
 
     {
-      "url": "guide/architecture",
       "title": "Fundamentals",
       "tooltip": "The fundamentals of Angular",
       "children": [

aio/e2e/app.e2e-spec.ts

@@ -1,4 +1,4 @@
-import { browser, by, element } from 'protractor';
+import { browser, by, element, ElementFinder } from 'protractor';
 import { SitePage } from './app.po';
 
 describe('site App', function() {
@@ -11,7 +11,7 @@ describe('site App', function() {
 
   it('should show features text after clicking "Features"', () => {
     page.navigateTo('');
-    page.getTopMenuLink('features').click();
+    page.click(page.getTopMenuLink('features'));
     expect(page.getDocViewerText()).toMatch(/Progressive web apps/i);
   });
 
@@ -19,28 +19,74 @@ describe('site App', function() {
     page.navigateTo('');
     expect(browser.getTitle()).toBe('Angular');
 
-    page.getTopMenuLink('features').click();
+    page.click(page.getTopMenuLink('features'));
     expect(browser.getTitle()).toBe('Angular - FEATURES & BENEFITS');
 
-    page.homeLink.click();
+    page.click(page.homeLink);
     expect(browser.getTitle()).toBe('Angular');
   });
 
+  it('should not navigate when clicking on nav-item headings (sub-menu toggles)', () => {
+    // Show the sidenav.
+    page.navigateTo('docs');
+    expect(page.locationPath()).toBe('/docs');
+
+    // Get the top-level nav-item headings (sub-menu toggles).
+    const navItemHeadings = page.getNavItemHeadings(page.sidenav, 1);
+
+    // Test all headings (and sub-headings).
+    expect(navItemHeadings.count()).toBeGreaterThan(0);
+    navItemHeadings.each(heading => testNavItemHeading(heading!, 1));
+
+    // Helpers
+    function expectToBeCollapsed(element: ElementFinder) {
+      expect(element.getAttribute('class')).toMatch(/\bcollapsed\b/);
+      expect(element.getAttribute('class')).not.toMatch(/\bexpanded\b/);
+    }
+
+    function expectToBeExpanded(element: ElementFinder) {
+      expect(element.getAttribute('class')).not.toMatch(/\bcollapsed\b/);
+      expect(element.getAttribute('class')).toMatch(/\bexpanded\b/);
+    }
+
+    function testNavItemHeading(heading: ElementFinder, level: number) {
+      const children = page.getNavItemHeadingChildren(heading, level);
+
+      // Headings are initially collapsed.
+      expectToBeCollapsed(children);
+
+      // Ensure heading does not cause navigation when expanding.
+      page.click(heading);
+      expectToBeExpanded(children);
+      expect(page.locationPath()).toBe('/docs');
+
+      // Recursively test child-headings (while this heading is expanded).
+      const nextLevel = level + 1;
+      const childNavItemHeadings = page.getNavItemHeadings(children, nextLevel);
+      childNavItemHeadings.each(childHeading => testNavItemHeading(childHeading!, nextLevel));
+
+      // Ensure heading does not cause navigation when collapsing.
+      page.click(heading);
+      expectToBeCollapsed(children);
+      expect(page.locationPath()).toBe('/docs');
+    }
+  });
+
   it('should show the tutorial index page at `/tutorial` after jitterbugging through features', () => {
     // check that we can navigate directly to the tutorial page
     page.navigateTo('tutorial');
     expect(page.getDocViewerText()).toMatch(/Tutorial: Tour of Heroes/i);
 
     // navigate to a different page
-    page.getTopMenuLink('features').click();
+    page.click(page.getTopMenuLink('features'));
     expect(page.getDocViewerText()).toMatch(/Progressive web apps/i);
 
     // Show the menu
-    page.docsMenuLink.click();
+    page.click(page.docsMenuLink);
 
     // Tutorial folder should still be expanded because this test runs in wide mode
     // Navigate to the tutorial introduction via a link in the sidenav
-    page.getNavItem(/introduction/i).click();
+    page.click(page.getNavItem(/introduction/i));
     expect(page.getDocViewerText()).toMatch(/Tutorial: Tour of Heroes/i);
   });
 
@@ -57,8 +103,7 @@ describe('site App', function() {
       page.scrollToBottom();
       expect(page.getScrollTop()).toBeGreaterThan(0);
 
-      page.getNavItem(/api/i).click();
+      page.click(page.getNavItem(/api/i));
-      browser.waitForAngular();
       expect(page.locationPath()).toBe('/api');
       expect(page.getScrollTop()).toBe(0);
     });
@@ -69,8 +114,7 @@ describe('site App', function() {
       page.scrollToBottom();
       expect(page.getScrollTop()).toBeGreaterThan(0);
 
-      page.getNavItem(/security/i).click();
+      page.click(page.getNavItem(/security/i));
-      browser.waitForAngular();
       expect(page.locationPath()).toBe('/guide/security');
       expect(page.getScrollTop()).toBe(0);
     });
@@ -102,7 +146,7 @@ describe('site App', function() {
     it('should call ga with new URL on navigation', done => {
       let path: string;
       page.navigateTo('');
-      page.getTopMenuLink('features').click();
+      page.click(page.getTopMenuLink('features'));
       page.locationPath()
         .then(p => path = p)
         .then(() => page.ga())
@@ -125,7 +169,7 @@ describe('site App', function() {
       expect(element(by.css('meta[name="googlebot"][content="noindex"]')).isPresent()).toBeTruthy();
       expect(element(by.css('meta[name="robots"][content="noindex"]')).isPresent()).toBeTruthy();
 
-      page.getTopMenuLink('features').click();
+      page.click(page.getTopMenuLink('features'));
       expect(element(by.css('meta[name="googlebot"]')).isPresent()).toBeFalsy();
       expect(element(by.css('meta[name="robots"]')).isPresent()).toBeFalsy();
     });

aio/e2e/app.po.ts

@@ -7,6 +7,7 @@ export class SitePage {
   links = element.all(by.css('md-toolbar a'));
   homeLink = element(by.css('a.home'));
   docsMenuLink = element(by.cssContainingText('aio-top-menu a', 'Docs'));
+  sidenav = element(by.css('mat-sidenav'));
   docViewer = element(by.css('aio-doc-viewer'));
   codeExample = element.all(by.css('aio-doc-viewer pre > code'));
   ghLink = this.docViewer
@@ -24,7 +25,17 @@ export class SitePage {
                   .filter(element => element.getText().then(text => pattern.test(text)))
                   .first();
   }
+  getNavItemHeadings(parent: ElementFinder, level: number) {
+    const targetSelector = `aio-nav-item .vertical-menu-item.heading.level-${level}`;
+    return parent.all(by.css(targetSelector));
+  }
+  getNavItemHeadingChildren(heading: ElementFinder, level: number) {
+    const targetSelector = `.heading-children.level-${level}`;
+    const script = `return arguments[0].parentNode.querySelector('${targetSelector}');`;
+    return element(() => browser.executeScript(script, heading));
+  }
   getTopMenuLink(path) { return element(by.css(`aio-top-menu a[href="${path}"]`)); }
+
   ga() { return browser.executeScript('return window["ga"].q') as promise.Promise<any[][]>; }
   locationPath() { return browser.executeScript('return document.location.pathname') as promise.Promise<string>; }
 
@@ -53,6 +64,10 @@ export class SitePage {
     return browser.executeScript('window.scrollTo(0, document.body.scrollHeight)');
   }
 
+  click(element: ElementFinder) {
+    return element.click().then(() => browser.waitForAngular());
+  }
+
   enterSearch(query: string) {
     const input = element(by.css('.search-container input[type=search]'));
     input.clear();

aio/src/styles/1-layouts/_sidenav.scss

@@ -128,6 +128,12 @@ button.vertical-menu-item {
   transition-timing-function: ease-out;
 }
 
+.no-animations {
+  .heading-children.expanded, .heading-children.collapsed {
+    transition: none! important;
+  }
+}
+
 .level-1 {
   font-family: $main-font;
   font-size: 14px;