aio: add h1 title to floating table of contents (#16959)

* refactor(aio): use explicit CSS class for TOC container

This makes the styling less fragile to changes in the HTML

* fix(aio): schedule TocComponent.activeIndex updates via AsapScheduler

We use the `asap` scheduler because updates to `activeItemIndex` are triggered by DOM changes,
which, in turn, are caused by the rendering that happened due to a ChangeDetection.

Without asap, we would be updating the model while still in a ChangeDetection handler,
which is disallowed by Angular.

* refactor(aio): do not instantiate floating ToC if not displayed

* feat(aio): display the h1 at the top of the floating TOC

Closes #16900

* refactor(aio): combine the TOC booleans flags into a "type" state

* refactor(aio): remove unnecessary `hostElement` property

* fix(aio): ensure that transition works on TOC

* fix(aio): use strict equality in ToC template

aio/src/app/app.component.html

@@ -35,9 +35,7 @@
 
 </md-sidenav-container>
 
-
+<div *ngIf="showFloatingToc" class="toc-container" [style.max-height.px]="tocMaxHeight">
-
-<div class="toc-container" [style.max-height.px]="tocMaxHeight">
   <aio-toc></aio-toc>
 </div>
 

aio/src/app/app.component.spec.ts

@@ -75,6 +75,13 @@ describe('AppComponent', () => {
         component.onResize(500);
         expect(component.isSideBySide).toBe(false);
       });
+
+      it('should update `showFloatingToc` accordingly', () => {
+        component.onResize(801);
+        expect(component.showFloatingToc).toBe(true);
+        component.onResize(800);
+        expect(component.showFloatingToc).toBe(false);
+      });
     });
 
     describe('onScroll', () => {

aio/src/app/app.component.ts

@@ -65,8 +65,12 @@ export class AppComponent implements OnInit {
   sideNavNodes: NavigationNode[];
   topMenuNodes: NavigationNode[];
   topMenuNarrowNodes: NavigationNode[];
+
+  showFloatingToc = false;
+  showFloatingTocWidth = 800;
   tocMaxHeight: string;
   private tocMaxHeightOffset = 0;
+
   versionInfo: VersionInfo;
 
   get homeImageUrl() {
@@ -198,6 +202,7 @@ export class AppComponent implements OnInit {
   @HostListener('window:resize', ['$event.target.innerWidth'])
   onResize(width) {
     this.isSideBySide = width > this.sideBySideWidth;
+    this.showFloatingToc = width > this.showFloatingTocWidth;
   }
 
   @HostListener('click', ['$event.target', '$event.button', '$event.ctrlKey', '$event.metaKey', '$event.altKey'])

aio/src/app/embedded/toc/toc.component.html

@@ -1,11 +1,11 @@
-<div *ngIf="hasToc" [class.collapsed]="isCollapsed">
+<div *ngIf="type !== 'None'" class="toc-inner" [class.collapsed]="isCollapsed">
-  <button *ngIf="!isEmbedded" type="button" class="toc-heading"
-    (click)="toTop()" title="Top of page">Contents</button>
 
-  <div *ngIf="!hasSecondary && isEmbedded" class="toc-heading embedded">Contents</div>
+  <div *ngIf="type === 'EmbeddedSimple'" class="toc-heading embedded">
+    Contents
+  </div>
 
-  <button *ngIf="hasSecondary" type="button" class="toc-heading embedded secondary"
+  <button *ngIf="type === 'EmbeddedExpandable'" type="button" (click)="toggle(false)"
-    (click)="toggle(false)"
+    class="toc-heading embedded secondary"
     title="Expand/collapse contents"
     aria-label="Expand/collapse contents"
     [attr.aria-pressed]="!isCollapsed">
@@ -14,13 +14,15 @@
   </button>
 
   <ul class="toc-list">
-    <li #tocItem *ngFor="let toc of tocList; let i = index" title="{{toc.title}}"
+    <ng-container *ngFor="let toc of tocList; let i = index">
-      class="{{toc.level}}" [class.secondary]="toc.isSecondary" [class.active]="i === activeIndex">
+      <li #tocItem title="{{toc.title}}" *ngIf="type === 'Floating' || toc.level !== 'h1'"
-      <a [href]="toc.href" [innerHTML]="toc.content"></a>
+        class="{{toc.level}}" [class.secondary]="type === 'EmbeddedExpandable' && i >= primaryMax" [class.active]="i === activeIndex">
-    </li>
+        <a [href]="toc.href" [innerHTML]="toc.content"></a>
+      </li>
+    </ng-container>
   </ul>
 
-  <button type="button" (click)="toggle()" *ngIf="hasSecondary"
+  <button *ngIf="type === 'EmbeddedExpandable'" type="button" (click)="toggle()"
     class="toc-more-items embedded material-icons" [class.collapsed]="isCollapsed"
     title="Expand/collapse contents"
     aria-label="Expand/collapse contents"

aio/src/app/embedded/toc/toc.component.spec.ts

@@ -1,7 +1,8 @@
 import { Component, CUSTOM_ELEMENTS_SCHEMA, DebugElement } from '@angular/core';
-import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+import { ComponentFixture, TestBed } from '@angular/core/testing';
 import { By, DOCUMENT } from '@angular/platform-browser';
 import { BehaviorSubject } from 'rxjs/BehaviorSubject';
+import { asap } from 'rxjs/scheduler/asap';
 
 import { ScrollService } from 'app/shared/scroll.service';
 import { TocComponent } from './toc.component';
@@ -16,7 +17,7 @@ describe('TocComponent', () => {
     listItems: DebugElement[];
     tocHeading: DebugElement;
     tocHeadingButtonEmbedded: DebugElement;
-    tocHeadingButtonSide: DebugElement;
+    tocH1Heading: DebugElement;
     tocMoreButton: DebugElement;
   };
 
@@ -25,7 +26,7 @@ describe('TocComponent', () => {
       listItems: tocComponentDe.queryAll(By.css('ul.toc-list>li')),
       tocHeading: tocComponentDe.query(By.css('.toc-heading')),
       tocHeadingButtonEmbedded: tocComponentDe.query(By.css('button.toc-heading.embedded')),
-      tocHeadingButtonSide: tocComponentDe.query(By.css('button.toc-heading:not(.embedded)')),
+      tocH1Heading: tocComponentDe.query(By.css('.h1')),
       tocMoreButton: tocComponentDe.query(By.css('button.toc-more-items')),
     };
   }
@@ -60,40 +61,51 @@ describe('TocComponent', () => {
     });
 
     it('should not display a ToC initially', () => {
-      expect(tocComponent.hasToc).toBe(false);
+      expect(tocComponent.type).toEqual('None');
     });
 
-    it('should not display anything when no TocItems', () => {
+    it('should not display anything when no h2 or h3 TocItems', () => {
-      tocService.tocList.next([]);
+      tocService.tocList.next([tocItem('H1', 'h1')]);
       fixture.detectChanges();
       expect(tocComponentDe.children.length).toEqual(0);
     });
 
     it('should update when the TocItems are updated', () => {
-      tocService.tocList.next([{}] as TocItem[]);
+      tocService.tocList.next([tocItem('Heading A')]);
       fixture.detectChanges();
       expect(tocComponentDe.queryAllNodes(By.css('li')).length).toBe(1);
 
-      tocService.tocList.next([{}, {}, {}] as TocItem[]);
+      tocService.tocList.next([tocItem('Heading A'), tocItem('Heading B'), tocItem('Heading C')]);
       fixture.detectChanges();
       expect(tocComponentDe.queryAllNodes(By.css('li')).length).toBe(3);
     });
 
+    it('should only display H2 and H3 TocItems', () => {
+      tocService.tocList.next([tocItem('Heading A', 'h1'), tocItem('Heading B'), tocItem('Heading C', 'h3')]);
+      fixture.detectChanges();
+      const items = tocComponentDe.queryAllNodes(By.css('li'));
+      expect(items.length).toBe(2);
+      expect(items.find(item => item.nativeNode.innerText === 'Heading A')).toBeFalsy();
+      expect(items.find(item => item.nativeNode.innerText === 'Heading B')).toBeTruthy();
+      expect(items.find(item => item.nativeNode.innerText === 'Heading C')).toBeTruthy();
+      expect(setPage().tocH1Heading).toBeFalsy();
+    });
+
     it('should stop listening for TocItems once destroyed', () => {
-      tocService.tocList.next([{}] as TocItem[]);
+      tocService.tocList.next([tocItem('Heading A')]);
       fixture.detectChanges();
       expect(tocComponentDe.queryAllNodes(By.css('li')).length).toBe(1);
 
       tocComponent.ngOnDestroy();
-      tocService.tocList.next([{}, {}, {}] as TocItem[]);
+      tocService.tocList.next([tocItem('Heading A', 'h1'), tocItem('Heading B'), tocItem('Heading C')]);
       fixture.detectChanges();
       expect(tocComponentDe.queryAllNodes(By.css('li')).length).toBe(1);
     });
 
-    describe('when four TocItems', () => {
+    describe('when fewer than `maxPrimary` TocItems', () => {
 
       beforeEach(() => {
-        tocService.tocList.next([{}, {}, {}, {}] as TocItem[]);
+        tocService.tocList.next([tocItem('Heading A'), tocItem('Heading B'), tocItem('Heading C'), tocItem('Heading D')]);
         fixture.detectChanges();
         page = setPage();
       });
@@ -103,7 +115,7 @@ describe('TocComponent', () => {
       });
 
       it('should not have secondary items', () => {
-        expect(tocComponent.hasSecondary).toEqual(false, 'hasSecondary flag');
+        expect(tocComponent.type).toEqual('EmbeddedSimple');
         const aSecond = page.listItems.find(item => item.classes.secondary);
         expect(aSecond).toBeFalsy('should not find a secondary');
       });
@@ -128,7 +140,10 @@ describe('TocComponent', () => {
         tocService.tocList.subscribe(v => tocList = v);
 
         expect(page.listItems.length).toBeGreaterThan(4);
-        expect(page.listItems.length).toEqual(tocList.length);
+      });
+
+      it('should not display the h1 item', () => {
+        expect(page.listItems.find(item => item.classes.h1)).toBeFalsy('should not find h1 item');
       });
 
       it('should be in "collapsed" (not expanded) state at the start', () => {
@@ -145,14 +160,13 @@ describe('TocComponent', () => {
       });
 
       it('should have secondary items', () => {
-        expect(tocComponent.hasSecondary).toEqual(true, 'hasSecondary flag');
+        expect(tocComponent.type).toEqual('EmbeddedExpandable');
       });
 
-      // CSS should hide items with the secondary class when collapsed
+      // CSS will hide items with the secondary class when collapsed
       it('should have secondary item with a secondary class', () => {
         const aSecondary = page.listItems.find(item => item.classes.secondary);
         expect(aSecondary).toBeTruthy('should find a secondary');
-        expect(aSecondary.classes.secondary).toEqual(true, 'has secondary class');
       });
 
       describe('after click tocHeading button', () => {
@@ -245,17 +259,15 @@ describe('TocComponent', () => {
 
     it('should not be in embedded state', () => {
       expect(tocComponent.isEmbedded).toEqual(false);
+      expect(tocComponent.type).toEqual('Floating');
     });
 
-    it('should display all items', () => {
+    it('should display all items (including h1s)', () => {
-      let tocList: TocItem[];
+      expect(page.listItems.length).toEqual(getTestTocList().length);
-      tocService.tocList.subscribe(v => tocList = v);
-
-      expect(page.listItems.length).toEqual(tocList.length);
     });
 
     it('should not have secondary items', () => {
-      expect(tocComponent.hasSecondary).toEqual(false, 'hasSecondary flag');
+      expect(tocComponent.type).toEqual('Floating');
       const aSecond = page.listItems.find(item => item.classes.secondary);
       expect(aSecond).toBeFalsy('should not find a secondary');
     });
@@ -265,37 +277,31 @@ describe('TocComponent', () => {
       expect(page.tocMoreButton).toBeFalsy('bottom more button');
     });
 
-    it('should display "Contents" button', () => {
+    it('should display H1 title', () => {
-      expect(page.tocHeadingButtonSide).toBeTruthy();
+      expect(page.tocH1Heading).toBeTruthy();
-    });
-
-    it('should scroll to top when "Contents" button clicked', () => {
-      page.tocHeadingButtonSide.nativeElement.click();
-      fixture.detectChanges();
-      expect(scrollToTopSpy).toHaveBeenCalled();
     });
 
     describe('#activeIndex', () => {
       it('should keep track of `TocService`\'s `activeItemIndex`', () => {
         expect(tocComponent.activeIndex).toBeNull();
 
-        tocService.activeItemIndex.next(42);
+        tocService.setActiveIndex(42);
         expect(tocComponent.activeIndex).toBe(42);
 
-        tocService.activeItemIndex.next(null);
+        tocService.setActiveIndex(null);
         expect(tocComponent.activeIndex).toBeNull();
       });
 
       it('should stop tracking `activeItemIndex` once destroyed', () => {
-        tocService.activeItemIndex.next(42);
+        tocService.setActiveIndex(42);
         expect(tocComponent.activeIndex).toBe(42);
 
         tocComponent.ngOnDestroy();
 
-        tocService.activeItemIndex.next(43);
+        tocService.setActiveIndex(43);
         expect(tocComponent.activeIndex).toBe(42);
 
-        tocService.activeItemIndex.next(null);
+        tocService.setActiveIndex(null);
         expect(tocComponent.activeIndex).toBe(42);
       });
 
@@ -334,19 +340,19 @@ describe('TocComponent', () => {
 
         tocComponent.activeIndex = 1;
         fixture.detectChanges();
-        expect(getActiveTextContent()).toBe('H2 Two');
+        expect(getActiveTextContent()).toBe('Heading one');
 
-        tocComponent.tocList = [{content: 'New 1'}, {content: 'New 2'}] as any as TocItem[];
+        tocComponent.tocList = [tocItem('New 1'), tocItem('New 2')];
         fixture.detectChanges();
         page = setPage();
         expect(getActiveTextContent()).toBe('New 2');
 
-        tocComponent.tocList.unshift({content: 'New 0'} as any as TocItem);
+        tocComponent.tocList.unshift(tocItem('New 0'));
         fixture.detectChanges();
         page = setPage();
         expect(getActiveTextContent()).toBe('New 1');
 
-        tocComponent.tocList = [{content: 'Very New 1'}] as any as TocItem[];
+        tocComponent.tocList = [tocItem('Very New 1')];
         fixture.detectChanges();
         page = setPage();
         expect(page.listItems.findIndex(By.css('.active'))).toBe(-1);
@@ -373,17 +379,17 @@ describe('TocComponent', () => {
         });
 
         it('when the `activeIndex` changes', () => {
-          tocService.activeItemIndex.next(0);
+          tocService.setActiveIndex(0);
           fixture.detectChanges();
 
           expect(parentScrollTop).toBe(0);
 
-          tocService.activeItemIndex.next(1);
+          tocService.setActiveIndex(1);
           fixture.detectChanges();
 
           expect(parentScrollTop).toBe(0);
 
-          tocService.activeItemIndex.next(page.listItems.length - 1);
+          tocService.setActiveIndex(page.listItems.length - 1);
           fixture.detectChanges();
 
           expect(parentScrollTop).toBeGreaterThan(0);
@@ -397,7 +403,7 @@ describe('TocComponent', () => {
 
           expect(parentScrollTop).toBe(0);
 
-          tocService.activeItemIndex.next(tocList.length - 1);
+          tocService.setActiveIndex(tocList.length - 1);
           fixture.detectChanges();
 
           expect(parentScrollTop).toBe(0);
@@ -412,7 +418,7 @@ describe('TocComponent', () => {
           const tocList = tocComponent.tocList;
           tocComponent.ngOnDestroy();
 
-          tocService.activeItemIndex.next(page.listItems.length - 1);
+          tocService.setActiveIndex(page.listItems.length - 1);
           fixture.detectChanges();
 
           expect(parentScrollTop).toBe(0);
@@ -453,46 +459,26 @@ class TestScrollService {
 class TestTocService {
   tocList = new BehaviorSubject<TocItem[]>(getTestTocList());
   activeItemIndex = new BehaviorSubject<number | null>(null);
+  setActiveIndex(index) {
+    this.activeItemIndex.next(index);
+    if (asap.scheduled) {
+      asap.flush();
+    }
+  }
+}
+
+function tocItem(title: string, level = 'h2', href = '', content = title) {
+  return { title, href, level, content };
 }
 
-// tslint:disable:quotemark
 function getTestTocList() {
   return [
-    {
+    tocItem('Title',       'h1', 'fizz/buzz#title',                  'Title'),
-      "content": "Heading one",
+    tocItem('Heading one', 'h2', 'fizz/buzz#heading-one-special-id', 'Heading one'),
-      "href": "fizz/buzz#heading-one-special-id",
+    tocItem('H2 Two',      'h2', 'fizz/buzz#h2-two',                 'H2 Two'),
-      "level": "h2",
+    tocItem('H2 Three',    'h2', 'fizz/buzz#h2-three',               'H2 <b>Three</b>'),
-      "title": "Heading one"
+    tocItem('H3 3a',       'h3', 'fizz/buzz#h3-3a',                  'H3 3a'),
-    },
+    tocItem('H3 3b',       'h3', 'fizz/buzz#h3-3b',                  'H3 3b'),
-    {
+    tocItem('H2 4',        'h2', 'fizz/buzz#h2-four',                '<i>H2 <b>four</b></i>'),
-      "content": "H2 Two",
-      "href": "fizz/buzz#h2-two",
-      "level": "h2",
-      "title": "H2 Two"
-    },
-    {
-      "content": "H2 <b>Three</b>",
-      "href": "fizz/buzz#h2-three",
-      "level": "h2",
-      "title": "H2 Three"
-    },
-    {
-      "content": "H3 3a",
-      "href": "fizz/buzz#h3-3a",
-      "level": "h3",
-      "title": "H3 3a"
-    },
-    {
-      "content": "H3 3b",
-      "href": "fizz/buzz#h3-3b",
-      "level": "h3",
-      "title": "H3 3b"
-    },
-    {
-      "content": "<i>H2 <b>four</b></i>",
-      "href": "fizz/buzz#h2-four",
-      "level": "h2",
-      "title": "H2 4"
-    }
   ];
 }

aio/src/app/embedded/toc/toc.component.ts

@@ -1,12 +1,16 @@
 import { AfterViewInit, Component, ElementRef, OnDestroy, OnInit, QueryList, ViewChildren } from '@angular/core';
 import { Observable } from 'rxjs/Observable';
 import { Subject } from 'rxjs/Subject';
+import { asap } from 'rxjs/scheduler/asap';
 import 'rxjs/add/observable/combineLatest';
+import 'rxjs/add/operator/subscribeOn';
 import 'rxjs/add/operator/takeUntil';
 
 import { ScrollService } from 'app/shared/scroll.service';
 import { TocItem, TocService } from 'app/shared/toc.service';
 
+type TocType = 'None' | 'Floating' | 'EmbeddedSimple' | 'EmbeddedExpandable';
+
 @Component({
   selector: 'aio-toc',
   templateUrl: 'toc.component.html',
@@ -15,9 +19,7 @@ import { TocItem, TocService } from 'app/shared/toc.service';
 export class TocComponent implements OnInit, AfterViewInit, OnDestroy {
 
   activeIndex: number | null = null;
-  hasSecondary = false;
+  type: TocType = 'None';
-  hasToc = false;
-  hostElement: HTMLElement;
   isCollapsed = true;
   isEmbedded = false;
   @ViewChildren('tocItem') private items: QueryList<ElementRef>;
@@ -29,37 +31,35 @@ export class TocComponent implements OnInit, AfterViewInit, OnDestroy {
     private scrollService: ScrollService,
     elementRef: ElementRef,
     private tocService: TocService) {
-    this.hostElement = elementRef.nativeElement;
+    this.isEmbedded = elementRef.nativeElement.className.indexOf('embedded') !== -1;
-    this.isEmbedded = this.hostElement.className.indexOf('embedded') !== -1;
   }
 
   ngOnInit() {
     this.tocService.tocList
         .takeUntil(this.onDestroy)
         .subscribe(tocList => {
-          const count = tocList.length;
-
-          this.hasToc = count > 0;
-          this.hasSecondary = this.isEmbedded && this.hasToc && (count > this.primaryMax);
           this.tocList = tocList;
+          const itemCount = count(this.tocList, item => item.level !== 'h1');
 
-          if (this.hasSecondary) {
+          this.type = (itemCount > 0) ?
-            for (let i = this.primaryMax; i < count; i++) {
+                        this.isEmbedded ?
-              tocList[i].isSecondary = true;
+                          (itemCount > this.primaryMax) ?
-            }
+                            'EmbeddedExpandable' :
-          }
+                          'EmbeddedSimple' :
+                        'Floating' :
+                      'None';
         });
   }
 
   ngAfterViewInit() {
     if (!this.isEmbedded) {
-      this.tocService.activeItemIndex
+      // We use the `asap` scheduler because updates to `activeItemIndex` are triggered by DOM changes,
-          .takeUntil(this.onDestroy)
+      // which, in turn, are caused by the rendering that happened due to a ChangeDetection.
-          .subscribe(index => this.activeIndex = index);
+      // Without asap, we would be updating the model while still in a ChangeDetection handler, which is disallowed by Angular.
-
+      Observable.combineLatest(this.tocService.activeItemIndex.subscribeOn(asap), this.items.changes.startWith(this.items))
-      Observable.combineLatest(this.tocService.activeItemIndex, this.items.changes.startWith(this.items))
           .takeUntil(this.onDestroy)
           .subscribe(([index, items]) => {
+            this.activeIndex = index;
             if (index === null || index >= items.length) {
               return;
             }
@@ -92,3 +92,7 @@ export class TocComponent implements OnInit, AfterViewInit, OnDestroy {
     this.scrollService.scrollToTop();
   }
 }
+
+function count<T>(array: T[], fn: (T) => boolean) {
+  return array.reduce((count, item) => fn(item) ? count + 1 : count, 0);
+}

aio/src/app/shared/toc.service.spec.ts

@@ -37,28 +37,28 @@ describe('TocService', () => {
 
   describe('tocList', () => {
     it('should emit the latest value to new subscribers', () => {
-      const expectedValue1 = {} as TocItem;
+      const expectedValue1 = tocItem('Heading A');
-      const expectedValue2 = {} as TocItem;
+      const expectedValue2 = tocItem('Heading B');
       let value1: TocItem[];
       let value2: TocItem[];
 
-      tocService.tocList.next([] as TocItem[]);
+      tocService.tocList.next([]);
       tocService.tocList.subscribe(v => value1 = v);
       expect(value1).toEqual([]);
 
-      tocService.tocList.next([expectedValue1, expectedValue2] as TocItem[]);
+      tocService.tocList.next([expectedValue1, expectedValue2]);
       tocService.tocList.subscribe(v => value2 = v);
       expect(value2).toEqual([expectedValue1, expectedValue2]);
     });
 
     it('should emit the same values to all subscribers', () => {
-      const expectedValue1 = {} as TocItem;
+      const expectedValue1 = tocItem('Heading A');
-      const expectedValue2 = {} as TocItem;
+      const expectedValue2 = tocItem('Heading B');
       const emittedValues: TocItem[][] = [];
 
       tocService.tocList.subscribe(v => emittedValues.push(v));
       tocService.tocList.subscribe(v => emittedValues.push(v));
-      tocService.tocList.next([expectedValue1, expectedValue2] as TocItem[]);
+      tocService.tocList.next([expectedValue1, expectedValue2]);
 
       expect(emittedValues).toEqual([
         [expectedValue1, expectedValue2],
@@ -153,7 +153,9 @@ describe('TocService', () => {
   describe('should clear tocList', () => {
     beforeEach(() => {
       // Start w/ dummy data from previous usage
-      tocService.tocList.next([{}, {}] as TocItem[]);
+      const expectedValue1 = tocItem('Heading A');
+      const expectedValue2 = tocItem('Heading B');
+      tocService.tocList.next([expectedValue1, expectedValue2]);
       expect(lastTocList).not.toEqual([]);
     });
 
@@ -172,8 +174,8 @@ describe('TocService', () => {
       expect(lastTocList).toEqual([]);
     });
 
-    it('when given doc element w/ headings other than h2 & h3', () => {
+    it('when given doc element w/ headings other than h1, h2 & h3', () => {
-      callGenToc('<h1>This</h1><h4>and</h4><h5>that</h5>');
+      callGenToc('<h4>and</h4><h5>that</h5>');
       expect(lastTocList).toEqual([]);
     });
 
@@ -232,60 +234,60 @@ describe('TocService', () => {
     });
 
     it('should have tocList with expect number of TocItems', () => {
-      // should ignore h1, h4, and the no-toc h2
+      // should ignore h4, and the no-toc h2
-      expect(lastTocList.length).toEqual(headings.length - 3);
+      expect(lastTocList.length).toEqual(headings.length - 2);
     });
 
     it('should have href with docId and heading\'s id', () => {
-      const tocItem = lastTocList[0];
+      const tocItem = lastTocList.find(item => item.title === 'Heading one');
       expect(tocItem.href).toEqual(`${docId}#heading-one-special-id`);
     });
 
     it('should have level "h2" for an <h2>', () => {
-      const tocItem = lastTocList[0];
+      const tocItem = lastTocList.find(item => item.title === 'Heading one');
       expect(tocItem.level).toEqual('h2');
     });
 
     it('should have level "h3" for an <h3>', () => {
-      const tocItem = lastTocList[3];
+      const tocItem = lastTocList.find(item => item.title === 'H3 3a');
       expect(tocItem.level).toEqual('h3');
     });
 
     it('should have title which is heading\'s innerText ', () => {
       const heading = headings[3];
-      const tocItem = lastTocList[2];
+      const tocItem = lastTocList[3];
       expect(heading.innerText).toEqual(tocItem.title);
     });
 
     it('should have "SafeHtml" content which is heading\'s innerHTML ', () => {
       const heading = headings[3];
-      const content = lastTocList[2].content;
+      const content = lastTocList[3].content;
       expect((<TestSafeHtml>content).changingThisBreaksApplicationSecurity)
         .toEqual(heading.innerHTML);
     });
 
     it('should calculate and set id of heading without an id', () => {
+      const tocItem = lastTocList.find(item => item.title === 'H2 Two');
       const id = headings[2].getAttribute('id');
       expect(id).toEqual('h2-two');
     });
 
     it('should have href with docId and calculated heading id', () => {
-      const tocItem = lastTocList[1];
+      const tocItem = lastTocList.find(item => item.title === 'H2 Two');
       expect(tocItem.href).toEqual(`${docId}#h2-two`);
     });
 
     it('should ignore HTML in heading when calculating id', () => {
       const id = headings[3].getAttribute('id');
-      const tocItem = lastTocList[2];
+      const tocItem = lastTocList[3];
       expect(id).toEqual('h2-three', 'heading id');
       expect(tocItem.href).toEqual(`${docId}#h2-three`, 'tocItem href');
     });
 
     it('should avoid repeating an id when calculating', () => {
-      const tocItem4a = lastTocList[5];
+      const tocItems = lastTocList.filter(item => item.title === 'H2 4 repeat');
-      const tocItem4b = lastTocList[6];
+      expect(tocItems[0].href).toEqual(`${docId}#h2-4-repeat`, 'first');
-      expect(tocItem4a.href).toEqual(`${docId}#h2-4-repeat`, 'first');
+      expect(tocItems[1].href).toEqual(`${docId}#h2-4-repeat-2`, 'second');
-      expect(tocItem4b.href).toEqual(`${docId}#h2-4-repeat-2`, 'second');
     });
   });
 
@@ -363,3 +365,7 @@ class MockScrollSpyService {
   }
 }
 
+function tocItem(title: string, level = 'h2', href = '', content = title) {
+  return { title, href, level, content };
+}
+

aio/src/app/shared/toc.service.ts

@@ -1,7 +1,6 @@
 import { Inject, Injectable } from '@angular/core';
 import { DOCUMENT, DomSanitizer, SafeHtml } from '@angular/platform-browser';
 import { ReplaySubject } from 'rxjs/ReplaySubject';
-
 import { ScrollSpyInfo, ScrollSpyService } from 'app/shared/scroll-spy.service';
 
 
@@ -66,7 +65,7 @@ export class TocService {
   }
 
   private findTocHeadings(docElement: Element): HTMLHeadingElement[] {
-    const headings = docElement.querySelectorAll('h2,h3');
+    const headings = docElement.querySelectorAll('h1,h2,h3');
     const skipNoTocHeadings = (heading: HTMLHeadingElement) => !/(?:no-toc|notoc)/i.test(heading.className);
 
     return Array.prototype.filter.call(headings, skipNoTocHeadings);

aio/src/styles/2-modules/_toc.scss

@@ -6,11 +6,6 @@
   bottom: 32px;
   overflow-y: auto;
   overflow-x: hidden;
-
-  @media (max-width: 800px) {
-    display: none;
-    width: 0;
-  }
 }
 
 aio-toc {
@@ -19,16 +14,9 @@ aio-toc {
       display: none;
     }
   }
-
-  &:not(.embedded) {
-    @media (max-width: 800px) {
-      display: none;
-    }
-  }
-
 }
 
-aio-toc > div {
+.toc-inner {
   border-left: 4px solid #4285f4;
   font-size: 13px;
   overflow-y: visible;
@@ -59,6 +47,7 @@ aio-toc > div {
     border: none;
     box-shadow: none;
     padding: 0;
+    text-align: start;
 
     &:focus.embedded {
       outline: none;
@@ -67,7 +56,8 @@ aio-toc > div {
   }
 
   button.toc-heading,
-  div.toc-heading {
+  div.toc-heading,
+  ul.toc-list li.h1 {
     font-size: 115%;
   }
 
@@ -131,10 +121,10 @@ aio-toc > div {
     margin: 6px 0;
     padding: 0;
     position: relative;
-    transition: all 0.3 ease-in-out;
+    transition: all 0.3s ease-in-out;
 
     a {
-      font-size: 12px;
+      font-size: inherit;
       color: lighten($darkgray, 10);
       display:table-cell;
       overflow: visible;
@@ -154,6 +144,17 @@ aio-toc > div {
   ul.toc-list li.h3 {
     margin-left: 15px;
   }
+
+  ul.toc-list li.h1:after {
+    content: "";
+    display: block;
+    height: 1px;
+    width: 40%;
+    margin: 24px 0px 10px;
+    background: #DBDBDB;
+    clear: both;
+  }
+
 }
 
 aio-toc.embedded > div.collapsed li.secondary {