diff --git a/aio/src/app/app.component.spec.ts b/aio/src/app/app.component.spec.ts
index 8e2e860d87..c1fc933c0a 100644
--- a/aio/src/app/app.component.spec.ts
+++ b/aio/src/app/app.component.spec.ts
@@ -635,61 +635,53 @@ describe('AppComponent', () => {
     });
 
     describe('aio-toc', () => {
-      let tocContainer: HTMLElement|null;
-      let toc: HTMLElement|null;
-
-      const setHasFloatingToc = (hasFloatingToc: boolean) => {
+      function setHasFloatingTocAndGetToc(hasFloatingToc: false): [null, null];
+      function setHasFloatingTocAndGetToc(hasFloatingToc: true): [HTMLElement, HTMLElement];
+      function setHasFloatingTocAndGetToc(hasFloatingToc: boolean) {
         component.hasFloatingToc = hasFloatingToc;
         fixture.detectChanges();
 
-        tocContainer = fixture.debugElement.nativeElement.querySelector('.toc-container');
-        toc = tocContainer && tocContainer.querySelector('aio-toc');
-      };
+        const tocContainer = fixture.debugElement.nativeElement.querySelector('.toc-container');
+        const toc = tocContainer && tocContainer.querySelector('aio-toc');
 
-
-      beforeEach(() => {
-        tocContainer = null;
-        toc = null;
-      });
+        return [toc, tocContainer];
+      }
 
       it('should show/hide `<aio-toc>` based on `hasFloatingToc`', () => {
-        expect(tocContainer).toBeFalsy();
-        expect(toc).toBeFalsy();
+        const [toc1, tocContainer1] = setHasFloatingTocAndGetToc(true);
+        expect(tocContainer1).toBeTruthy();
+        expect(toc1).toBeTruthy();
 
-        setHasFloatingToc(true);
-        expect(tocContainer).toBeTruthy();
-        expect(toc).toBeTruthy();
-
-        setHasFloatingToc(false);
-        expect(tocContainer).toBeFalsy();
-        expect(toc).toBeFalsy();
+        const [toc2, tocContainer2] = setHasFloatingTocAndGetToc(false);
+        expect(tocContainer2).toBeFalsy();
+        expect(toc2).toBeFalsy();
       });
 
       it('should have a non-embedded `<aio-toc>` element', () => {
-        setHasFloatingToc(true);
-        expect(toc!.classList.contains('embedded')).toBe(false);
+        const [toc] = setHasFloatingTocAndGetToc(true);
+        expect(toc.classList.contains('embedded')).toBe(false);
       });
 
       it('should update the TOC container\'s `maxHeight` based on `tocMaxHeight`', () => {
-        setHasFloatingToc(true);
+        const [, tocContainer] = setHasFloatingTocAndGetToc(true);
 
         component.tocMaxHeight = '100';
         fixture.detectChanges();
-        expect(tocContainer!.style.maxHeight).toBe('100px');
+        expect(tocContainer.style.maxHeight).toBe('100px');
 
         component.tocMaxHeight = '200';
         fixture.detectChanges();
-        expect(tocContainer!.style.maxHeight).toBe('200px');
+        expect(tocContainer.style.maxHeight).toBe('200px');
       });
 
       it('should restrain scrolling inside the ToC container', () => {
         const restrainScrolling = spyOn(component, 'restrainScrolling');
         const evt = new WheelEvent('wheel');
+        const [, tocContainer] = setHasFloatingTocAndGetToc(true);
 
-        setHasFloatingToc(true);
         expect(restrainScrolling).not.toHaveBeenCalled();
 
-        tocContainer!.dispatchEvent(evt);
+        tocContainer.dispatchEvent(evt);
         expect(restrainScrolling).toHaveBeenCalledWith(evt);
       });
 
@@ -697,7 +689,7 @@ describe('AppComponent', () => {
         const loader = fixture.debugElement.injector.get(ElementsLoader) as unknown as TestElementsLoader;
         expect(loader.loadCustomElement).not.toHaveBeenCalled();
 
-        setHasFloatingToc(true);
+        setHasFloatingTocAndGetToc(true);
         expect(loader.loadCustomElement).toHaveBeenCalledWith('aio-toc');
       });
     });
@@ -721,7 +713,7 @@ describe('AppComponent', () => {
         createTestingModule('a/b', 'stable');
         await initializeTest();
         const banner: HTMLElement = fixture.debugElement.query(By.css('aio-mode-banner')).nativeElement;
-        expect(banner.textContent!.trim()).toEqual('');
+        expect(banner.textContent?.trim()).toEqual('');
       });
     });
 
@@ -1355,10 +1347,10 @@ class TestHttpClient {
     if (/navigation\.json/.test(url)) {
       data = this.navJson;
     } else {
-      const match = /generated\/docs\/(.+)\.json/.exec(url)!;
-      const id = match[1]!;
+      const match = /generated\/docs\/(.+)\.json/.exec(url);
+      const id = match?.[1];
       // Make up a title for test purposes
-      const title = id.split('/').pop()!.replace(/^([a-z])/, (_, letter) => letter.toUpperCase());
+      const title = id?.split('/')?.pop()?.replace(/^([a-z])/, (_, letter) => letter.toUpperCase());
       const h1 = (id === 'no-title') ? '' : `<h1 class="no-toc">${title}</h1>`;
       const contents = `${h1}<h2 id="#somewhere">Some heading</h2>`;
       data = { id, contents };
diff --git a/aio/src/app/app.component.ts b/aio/src/app/app.component.ts
index 90a03ae382..c90c41d5c8 100644
--- a/aio/src/app/app.component.ts
+++ b/aio/src/app/app.component.ts
@@ -163,7 +163,7 @@ export class AppComponent implements OnInit {
       // Find the current version - eithers title matches the current deployment mode
       // or its title matches the major version of the current version info
       this.currentDocVersion = this.docVersions.find(version =>
-        version.title === this.deployment.mode || version.title === `v${versionInfo.major}`)!;
+        version.title === this.deployment.mode || version.title === `v${versionInfo.major}`) as NavigationNode;
       this.currentDocVersion.title += ` (v${versionInfo.raw})`;
     });
 
diff --git a/aio/src/app/custom-elements/announcement-bar/announcement-bar.component.spec.ts b/aio/src/app/custom-elements/announcement-bar/announcement-bar.component.spec.ts
index ddd274d0b2..f18fa9a9b1 100644
--- a/aio/src/app/custom-elements/announcement-bar/announcement-bar.component.spec.ts
+++ b/aio/src/app/custom-elements/announcement-bar/announcement-bar.component.spec.ts
@@ -102,11 +102,11 @@ describe('AnnouncementBarComponent', () => {
     });
 
     it('should display an image', () => {
-      expect(element.querySelector('img')!.src).toContain('dummy/image');
+      expect(element.querySelector('img')?.src).toContain('dummy/image');
     });
 
     it('should display a link', () => {
-      expect(element.querySelector('a')!.href).toContain('link/to/website');
+      expect(element.querySelector('a')?.href).toContain('link/to/website');
     });
   });
 });
diff --git a/aio/src/app/custom-elements/api/api-list.component.spec.ts b/aio/src/app/custom-elements/api/api-list.component.spec.ts
index fb97db2c38..2c33324d5b 100644
--- a/aio/src/app/custom-elements/api/api-list.component.spec.ts
+++ b/aio/src/app/custom-elements/api/api-list.component.spec.ts
@@ -38,7 +38,7 @@ describe('ApiListComponent', () => {
     component.filteredSections.subscribe(filtered => {
       filtered = filtered.filter(section => section.items);
       expect(filtered.length).toBeGreaterThan(0, 'expected something');
-      expect(filtered.every(section => section.items!.every(itemTest))).toBe(true, label);
+      expect(filtered.every(section => section.items?.every(itemTest))).toBe(true, label);
     });
   }
 
@@ -66,7 +66,7 @@ describe('ApiListComponent', () => {
         filtered = filtered.filter(section => Array.isArray(section.items));
         expect(filtered.length).toBe(1, 'only one section');
         expect(filtered[0].name).toBe('core');
-        expect(filtered[0].items).toEqual(sections.find(section => section.name === 'core')!.items);
+        expect(filtered[0].items).toEqual(sections.find(section => section.name === 'core')?.items as ApiItem[]);
       });
     });
 
@@ -74,8 +74,8 @@ describe('ApiListComponent', () => {
       it('should null if there are no matching items and the section itself does not match', () => {
         component.setQuery('core');
         component.filteredSections.subscribe(filtered => {
-          const commonSection = filtered.find(section => section.name === 'common')!;
-          expect(commonSection.items).toBe(null);
+          const commonSection = filtered.find(section => section.name === 'common');
+          expect(commonSection?.items).toBe(null);
         });
       });
 
@@ -117,7 +117,7 @@ describe('ApiListComponent', () => {
         filtered = filtered.filter(s => s.items);
         expect(filtered.length).toBe(1, 'sections');
         expect(filtered[0].name).toBe(section, 'section name');
-        const items = filtered[0].items!;
+        const items = filtered[0].items as ApiItem[];
         expect(items.length).toBe(1, 'items');
 
         const item = items[0];
diff --git a/aio/src/app/custom-elements/api/api-list.component.ts b/aio/src/app/custom-elements/api/api-list.component.ts
index 836aab8e03..0950f4f29a 100644
--- a/aio/src/app/custom-elements/api/api-list.component.ts
+++ b/aio/src/app/custom-elements/api/api-list.component.ts
@@ -17,9 +17,9 @@ import { Option } from 'app/shared/select/select.component';
 import { map } from 'rxjs/operators';
 
 class SearchCriteria {
-  query ? = '';
-  status ? = 'all';
-  type ? = 'all';
+  query = '';
+  status = 'all';
+  type = 'all';
 }
 
 @Component({
@@ -116,13 +116,13 @@ export class ApiListComponent implements OnInit {
     const sectionNameMatches = !query || section.name.indexOf(query) !== -1;
 
     const matchesQuery = (item: ApiItem) =>
-      sectionNameMatches || item.name.indexOf(query!) !== -1;
+      sectionNameMatches || item.name.indexOf(query) !== -1;
     const matchesStatus = (item: ApiItem) =>
       status === 'all' || status === item.stability || (status === 'security-risk' && item.securityRisk);
     const matchesType = (item: ApiItem) =>
       type === 'all' || type === item.docType;
 
-    const items = section.items!.filter(item =>
+    const items: ApiItem[] = (section.items || []).filter(item =>
       matchesType(item) && matchesStatus(item) && matchesQuery(item));
 
     // If there are no items we still return an empty array if the section name matches and the type is 'package'
@@ -160,7 +160,7 @@ export class ApiListComponent implements OnInit {
     this.locationService.setSearch('API Search', params);
   }
 
-  private setSearchCriteria(criteria: SearchCriteria) {
+  private setSearchCriteria(criteria: Partial<SearchCriteria>) {
     this.criteriaSubject.next(Object.assign(this.searchCriteria, criteria));
     this.setLocationSearch();
   }
diff --git a/aio/src/app/custom-elements/code/code.component.spec.ts b/aio/src/app/custom-elements/code/code.component.spec.ts
index 1a93817245..88223c218b 100644
--- a/aio/src/app/custom-elements/code/code.component.spec.ts
+++ b/aio/src/app/custom-elements/code/code.component.spec.ts
@@ -251,7 +251,7 @@ describe('CodeComponent', () => {
         actualCode = spy.calls.mostRecent().args[0];
 
         expect(actualCode).toBe(expectedCode, `when linenums=${linenums}`);
-        expect(actualCode.match(/\r?\n/g)!.length).toBe(5);
+        expect(actualCode.match(/\r?\n/g)?.length).toBe(5);
 
         spy.calls.reset();
       });
diff --git a/aio/src/app/custom-elements/elements-loader.ts b/aio/src/app/custom-elements/elements-loader.ts
index f06894082b..73b1c10522 100644
--- a/aio/src/app/custom-elements/elements-loader.ts
+++ b/aio/src/app/custom-elements/elements-loader.ts
@@ -45,12 +45,12 @@ export class ElementsLoader {
   loadCustomElement(selector: string): Promise<void> {
     if (this.elementsLoading.has(selector)) {
       // The custom element is in the process of being loaded and registered.
-      return this.elementsLoading.get(selector)!;
+      return this.elementsLoading.get(selector) as Promise<void>;
     }
 
     if (this.elementsToLoad.has(selector)) {
       // Load and register the custom element (for the first time).
-      const modulePathLoader = this.elementsToLoad.get(selector)!;
+      const modulePathLoader = this.elementsToLoad.get(selector) as LoadChildrenCallback;
       const loadedAndRegistered =
           (modulePathLoader() as Promise<NgModuleFactory<WithCustomElementComponent> | Type<WithCustomElementComponent>>)
           .then(elementModuleOrFactory => {
@@ -73,7 +73,7 @@ export class ElementsLoader {
             const CustomElementComponent = elementModuleRef.instance.customElementComponent;
             const CustomElement = createCustomElement(CustomElementComponent, {injector});
 
-            customElements!.define(selector, CustomElement);
+            customElements.define(selector, CustomElement);
             return customElements.whenDefined(selector);
           })
           .then(() => {
diff --git a/aio/src/app/custom-elements/toc/toc.component.spec.ts b/aio/src/app/custom-elements/toc/toc.component.spec.ts
index 3dc17586cb..6149ab4018 100644
--- a/aio/src/app/custom-elements/toc/toc.component.spec.ts
+++ b/aio/src/app/custom-elements/toc/toc.component.spec.ts
@@ -337,7 +337,7 @@ describe('TocComponent', () => {
 
       it('should re-apply the `active` class when the list elements change', () => {
         const getActiveTextContent = () =>
-            page.listItems.find(By.css('.active'))!.nativeElement.textContent.trim();
+            page.listItems.find(By.css('.active'))?.nativeElement.textContent.trim();
 
         tocComponent.activeIndex = 1;
         fixture.detectChanges();
diff --git a/aio/src/app/documents/document.service.ts b/aio/src/app/documents/document.service.ts
index 83a5da9e33..168e6e71c8 100644
--- a/aio/src/app/documents/document.service.ts
+++ b/aio/src/app/documents/document.service.ts
@@ -49,7 +49,7 @@ export class DocumentService {
     if (!this.cache.has(id)) {
       this.cache.set(id, this.fetchDocument(id));
     }
-    return this.cache.get(id)!;
+    return this.cache.get(id) as Observable<DocumentContents>;
   }
 
   private fetchDocument(id: string): Observable<DocumentContents> {
diff --git a/aio/src/app/layout/doc-viewer/doc-viewer.component.spec.ts b/aio/src/app/layout/doc-viewer/doc-viewer.component.spec.ts
index 6aabeb6629..ca477216ac 100644
--- a/aio/src/app/layout/doc-viewer/doc-viewer.component.spec.ts
+++ b/aio/src/app/layout/doc-viewer/doc-viewer.component.spec.ts
@@ -213,10 +213,10 @@ describe('DocViewerComponent', () => {
       describe('needed', () => {
         it('should add an embedded ToC element if there is an `<h1>` heading', () => {
           doPrepareTitleAndToc(DOC_WITH_H1);
-          const tocEl = getTocEl()!;
+          const tocEl = getTocEl();
 
           expect(tocEl).toBeTruthy();
-          expect(tocEl.classList.contains('embedded')).toBe(true);
+          expect(tocEl?.classList.contains('embedded')).toBe(true);
         });
 
         it('should not add a second ToC element if there a hard coded one in place', () => {
diff --git a/aio/src/app/layout/doc-viewer/doc-viewer.component.ts b/aio/src/app/layout/doc-viewer/doc-viewer.component.ts
index 0fce7f88cd..5a5ed3f4d0 100644
--- a/aio/src/app/layout/doc-viewer/doc-viewer.component.ts
+++ b/aio/src/app/layout/doc-viewer/doc-viewer.component.ts
@@ -98,9 +98,9 @@ export class DocViewerComponent implements OnDestroy {
     const needsToc = !!titleEl && !/no-?toc/i.test(titleEl.className);
     const embeddedToc = targetElem.querySelector('aio-toc.embedded');
 
-    if (needsToc && !embeddedToc) {
+    if (titleEl && needsToc && !embeddedToc) {
       // Add an embedded ToC if it's needed and there isn't one in the content already.
-      titleEl!.insertAdjacentHTML('afterend', '<aio-toc class="embedded"></aio-toc>');
+      titleEl.insertAdjacentHTML('afterend', '<aio-toc class="embedded"></aio-toc>');
     } else if (!needsToc && embeddedToc && embeddedToc.parentNode !== null) {
       // Remove the embedded Toc if it's there and not needed.
       // We cannot use ChildNode.remove() because of IE11
@@ -223,7 +223,7 @@ export class DocViewerComponent implements OnDestroy {
       done$ = done$.pipe(
           // Remove the current view from the viewer.
           switchMap(() => animateLeave(this.currViewContainer)),
-          tap(() => this.currViewContainer.parentElement!.removeChild(this.currViewContainer)),
+          tap(() => (this.currViewContainer.parentElement as HTMLElement).removeChild(this.currViewContainer)),
           tap(() => this.docRemoved.emit()),
       );
     }
diff --git a/aio/src/app/navigation/navigation.service.spec.ts b/aio/src/app/navigation/navigation.service.spec.ts
index 96fc80b95b..373c2f77ad 100644
--- a/aio/src/app/navigation/navigation.service.spec.ts
+++ b/aio/src/app/navigation/navigation.service.spec.ts
@@ -144,7 +144,7 @@ describe('NavigationService', () => {
           url: 'b',
           view: 'SideNav',
           nodes: [
-            sideNavNodes[0].children![0],
+            sideNavNodes[0].children?.[0] as NavigationNode,
             sideNavNodes[0]
           ]
         }
@@ -156,8 +156,8 @@ describe('NavigationService', () => {
           url: 'd',
           view: 'SideNav',
           nodes: [
-            sideNavNodes[0].children![0].children![1],
-            sideNavNodes[0].children![0],
+            sideNavNodes[0].children?.[0].children?.[1] as NavigationNode,
+            sideNavNodes[0].children?.[0] as NavigationNode,
             sideNavNodes[0]
           ]
         }
@@ -201,8 +201,8 @@ describe('NavigationService', () => {
           url: 'c',
           view: 'SideNav',
           nodes: [
-            sideNavNodes[0].children![0].children![0],
-            sideNavNodes[0].children![0],
+            sideNavNodes[0].children?.[0].children?.[0] as NavigationNode,
+            sideNavNodes[0].children?.[0] as NavigationNode,
             sideNavNodes[0]
           ]
         }
diff --git a/aio/src/app/navigation/navigation.service.ts b/aio/src/app/navigation/navigation.service.ts
index 06162678ff..bf3e08a71b 100644
--- a/aio/src/app/navigation/navigation.service.ts
+++ b/aio/src/app/navigation/navigation.service.ts
@@ -153,7 +153,7 @@ export class NavigationService {
         if (!navMap.has(cleanedUrl)) {
           navMap.set(cleanedUrl, {});
         }
-        const navMapItem = navMap.get(cleanedUrl)!;
+        const navMapItem = navMap.get(cleanedUrl) as CurrentNodes;
         navMapItem[view] = { url, view, nodes };
       }
 
diff --git a/aio/src/app/shared/attribute-utils.spec.ts b/aio/src/app/shared/attribute-utils.spec.ts
index dd0ee2c265..25246a4ea9 100644
--- a/aio/src/app/shared/attribute-utils.spec.ts
+++ b/aio/src/app/shared/attribute-utils.spec.ts
@@ -8,7 +8,7 @@ describe('Attribute Utilities', () => {
   beforeEach(() => {
     const div = document.createElement('div');
     div.innerHTML = `<div a b="true" c="false" D="foo" d-E></div>`;
-    testEl = div.querySelector('div')!;
+    testEl = div.querySelector('div') as HTMLElement;
   });
 
   describe('getAttrs', () => {
diff --git a/aio/src/app/shared/copier.service.ts b/aio/src/app/shared/copier.service.ts
index 4b571de452..1a5c97ccac 100644
--- a/aio/src/app/shared/copier.service.ts
+++ b/aio/src/app/shared/copier.service.ts
@@ -44,7 +44,7 @@ export class CopierService {
    * @return The temporary `<textarea>` element containing the specified text.
    */
   private createTextArea(text: string): HTMLTextAreaElement {
-    const docElem = document.documentElement!;
+    const docElem = document.documentElement;
     const isRTL = docElem.getAttribute('dir') === 'rtl';
 
     // Create a temporary element to hold the contents to copy.
diff --git a/aio/src/app/shared/custom-icon-registry.spec.ts b/aio/src/app/shared/custom-icon-registry.spec.ts
index 45f6fe458b..9c017859a6 100644
--- a/aio/src/app/shared/custom-icon-registry.spec.ts
+++ b/aio/src/app/shared/custom-icon-registry.spec.ts
@@ -65,5 +65,5 @@ describe('CustomIconRegistry', () => {
 function createSvg(svgSrc: string): SVGElement {
   const div = document.createElement('div');
   div.innerHTML = svgSrc;
-  return div.querySelector('svg')!;
+  return div.querySelector('svg') as SVGElement;
 }
diff --git a/aio/src/app/shared/custom-icon-registry.ts b/aio/src/app/shared/custom-icon-registry.ts
index 5400b88e01..8ad73b2a29 100644
--- a/aio/src/app/shared/custom-icon-registry.ts
+++ b/aio/src/app/shared/custom-icon-registry.ts
@@ -78,7 +78,7 @@ export class CustomIconRegistry extends MatIconRegistry {
     // SECURITY: the source for the SVG icons is provided in code by trusted developers
     div.innerHTML = svgIcon.svgSource;
 
-    const svgElement = div.querySelector('svg')!;
+    const svgElement = div.querySelector('svg') as SVGElement;
     nsIconMap[svgIcon.name] = svgElement;
 
     return svgElement;
diff --git a/aio/src/app/shared/scroll-spy.service.spec.ts b/aio/src/app/shared/scroll-spy.service.spec.ts
index 9184839fa5..1cc9956fcc 100644
--- a/aio/src/app/shared/scroll-spy.service.spec.ts
+++ b/aio/src/app/shared/scroll-spy.service.spec.ts
@@ -235,7 +235,7 @@ describe('ScrollSpyService', () => {
 
     it('should remember and emit the last active item to new subscribers', () => {
       const items = [{index: 1}, {index: 2}, {index: 3}] as ScrollItem[];
-      let lastActiveItem: ScrollItem|null;
+      let lastActiveItem = null as unknown as ScrollItem|null;
 
       const info = scrollSpyService.spyOn([]);
       const spiedElemGroup = getSpiedElemGroups()[0];
@@ -247,12 +247,12 @@ describe('ScrollSpyService', () => {
       spiedElemGroup.activeScrollItem.next(items[1]);
       info.active.subscribe(item => lastActiveItem = item);
 
-      expect(lastActiveItem!).toBe(items[1]);
+      expect(lastActiveItem).toBe(items[1]);
 
       spiedElemGroup.activeScrollItem.next(null);
       info.active.subscribe(item => lastActiveItem = item);
 
-      expect(lastActiveItem!).toBeNull();
+      expect(lastActiveItem).toBeNull();
     });
 
     it('should only emit distinct values on `active`', () => {
diff --git a/aio/src/app/shared/scroll.service.spec.ts b/aio/src/app/shared/scroll.service.spec.ts
index 1a8c19db73..fa6f087251 100644
--- a/aio/src/app/shared/scroll.service.spec.ts
+++ b/aio/src/app/shared/scroll.service.spec.ts
@@ -114,7 +114,7 @@ describe('ScrollService', () => {
 
   it('should not break when cookies are disabled in the browser', () => {
     expect(() => {
-      const originalSessionStorage = Object.getOwnPropertyDescriptor(window, 'sessionStorage')!;
+      const originalSessionStorage = Object.getOwnPropertyDescriptor(window, 'sessionStorage') as PropertyDescriptor;
 
       try {
         // Simulate `window.sessionStorage` being inaccessible, when cookies are disabled.
diff --git a/aio/src/app/shared/scroll.service.ts b/aio/src/app/shared/scroll.service.ts
index 20b133055b..0788c3200e 100644
--- a/aio/src/app/shared/scroll.service.ts
+++ b/aio/src/app/shared/scroll.service.ts
@@ -33,7 +33,7 @@ export class ScrollService implements OnDestroy {
       const toolbar = this.document.querySelector('.app-toolbar');
       this._topOffset = (toolbar && toolbar.clientHeight || 0) + topMargin;
     }
-    return this._topOffset!;
+    return this._topOffset as number;
   }
 
   get topOfPageElement() {
diff --git a/aio/src/app/shared/search-results/search-results.component.ts b/aio/src/app/shared/search-results/search-results.component.ts
index c73efd30b0..7703cdc699 100644
--- a/aio/src/app/shared/search-results/search-results.component.ts
+++ b/aio/src/app/shared/search-results/search-results.component.ts
@@ -98,10 +98,10 @@ function splitPages(allPages: SearchResult[]) {
     }
   });
   while (priorityPages.length < 5 && pages.length) {
-    priorityPages.push(pages.shift()!);
+    priorityPages.push(pages.shift() as SearchResult);
   }
   while (priorityPages.length < 5 && deprecated.length) {
-    priorityPages.push(deprecated.shift()!);
+    priorityPages.push(deprecated.shift() as SearchResult);
   }
   pages.sort(compareResults);
 
diff --git a/aio/src/app/shared/select/select.component.spec.ts b/aio/src/app/shared/select/select.component.spec.ts
index cb71370a94..d8d4d04cc5 100644
--- a/aio/src/app/shared/select/select.component.spec.ts
+++ b/aio/src/app/shared/select/select.component.spec.ts
@@ -35,10 +35,10 @@ describe('SelectComponent', () => {
 
   describe('button', () => {
     it('should display the label if provided', () => {
-      expect(getButton().textContent!.trim()).toEqual('');
+      expect(getButton().textContent?.trim()).toEqual('');
       host.label = 'Label:';
       fixture.detectChanges();
-      expect(getButton().textContent!.trim()).toEqual('Label:');
+      expect(getButton().textContent?.trim()).toEqual('Label:');
     });
 
     it('should contain a symbol if hasSymbol is true', () => {
@@ -53,7 +53,7 @@ describe('SelectComponent', () => {
       host.selected = options[0];
       fixture.detectChanges();
       expect(getButton().textContent).toContain(options[0].title);
-      expect(getButtonSymbol()!.className).toContain(options[0].value);
+      expect(getButtonSymbol()?.className).toContain(options[0].value);
     });
 
     it('should toggle the visibility of the options list when clicked', () => {
@@ -108,7 +108,7 @@ describe('SelectComponent', () => {
       fixture.detectChanges();
       expect(host.onChange).toHaveBeenCalledWith({ option: options[0], index: 0 });
       expect(getButton().textContent).toContain(options[0].title);
-      expect(getButtonSymbol()!.className).toContain(options[0].value);
+      expect(getButtonSymbol()?.className).toContain(options[0].value);
     });
 
     it('should select the current option when enter is pressed', () => {
@@ -117,7 +117,7 @@ describe('SelectComponent', () => {
       fixture.detectChanges();
       expect(host.onChange).toHaveBeenCalledWith({ option: options[0], index: 0 });
       expect(getButton().textContent).toContain(options[0].title);
-      expect(getButtonSymbol()!.className).toContain(options[0].value);
+      expect(getButtonSymbol()?.className).toContain(options[0].value);
     });
 
     it('should select the current option when space is pressed', () => {
@@ -126,7 +126,7 @@ describe('SelectComponent', () => {
       fixture.detectChanges();
       expect(host.onChange).toHaveBeenCalledWith({ option: options[0], index: 0 });
       expect(getButton().textContent).toContain(options[0].title);
-      expect(getButtonSymbol()!.className).toContain(options[0].value);
+      expect(getButtonSymbol()?.className).toContain(options[0].value);
     });
 
     it('should hide when an option is clicked', () => {
diff --git a/aio/src/app/shared/toc.service.spec.ts b/aio/src/app/shared/toc.service.spec.ts
index be5cd36fe5..08435b3d9e 100644
--- a/aio/src/app/shared/toc.service.spec.ts
+++ b/aio/src/app/shared/toc.service.spec.ts
@@ -237,23 +237,23 @@ describe('TocService', () => {
     });
 
     it('should have href with docId and heading\'s id', () => {
-      const tocItem = lastTocList.find(item => item.title === 'Heading one')!;
-      expect(tocItem.href).toEqual(`${docId}#heading-one-special-id`);
+      const tocItem = lastTocList.find(item => item.title === 'Heading one');
+      expect(tocItem?.href).toEqual(`${docId}#heading-one-special-id`);
     });
 
     it('should have level "h1" for an <h1>', () => {
-      const tocItem = lastTocList.find(item => item.title === 'Fun with TOC')!;
-      expect(tocItem.level).toEqual('h1');
+      const tocItem = lastTocList.find(item => item.title === 'Fun with TOC');
+      expect(tocItem?.level).toEqual('h1');
     });
 
     it('should have level "h2" for an <h2>', () => {
-      const tocItem = lastTocList.find(item => item.title === 'Heading one')!;
-      expect(tocItem.level).toEqual('h2');
+      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.find(item => item.title === 'H3 3a')!;
-      expect(tocItem.level).toEqual('h3');
+      const tocItem = lastTocList.find(item => item.title === 'H3 3a');
+      expect(tocItem?.level).toEqual('h3');
     });
 
     it('should have title which is heading\'s textContent ', () => {
@@ -275,8 +275,8 @@ describe('TocService', () => {
     });
 
     it('should have href with docId and calculated heading id', () => {
-      const tocItem = lastTocList.find(item => item.title === 'H2 Two')!;
-      expect(tocItem.href).toEqual(`${docId}#h2-two`);
+      const tocItem = lastTocList.find(item => item.title === 'H2 Two');
+      expect(tocItem?.href).toEqual(`${docId}#h2-two`);
     });
 
     it('should ignore HTML in heading when calculating id', () => {
diff --git a/aio/src/app/shared/toc.service.ts b/aio/src/app/shared/toc.service.ts
index 3ef5d522bd..aea59adc96 100644
--- a/aio/src/app/shared/toc.service.ts
+++ b/aio/src/app/shared/toc.service.ts
@@ -70,7 +70,7 @@ export class TocService {
     // Remove any remaining `a` elements (but keep their content).
     querySelectorAll(div, 'a').forEach(anchorLink => {
       // We want to keep the content of this anchor, so move it into its parent.
-      const parent = anchorLink.parentNode!;
+      const parent = anchorLink.parentNode as Node;
       while (anchorLink.childNodes.length) {
         parent.insertBefore(anchorLink.childNodes[0], anchorLink);
       }
diff --git a/aio/src/testing/location.service.ts b/aio/src/testing/location.service.ts
index 2991580801..429dde495b 100644
--- a/aio/src/testing/location.service.ts
+++ b/aio/src/testing/location.service.ts
@@ -5,7 +5,7 @@ export class MockLocationService {
   urlSubject = new BehaviorSubject<string>(this.initialUrl);
   currentUrl = this.urlSubject.asObservable().pipe(map(url => this.stripSlashes(url)));
   // strip off query and hash
-  currentPath = this.currentUrl.pipe(map(url => url.match(/[^?#]*/)![0]));
+  currentPath = this.currentUrl.pipe(map(url => url.match(/[^?#]*/)?.[0] || ''));
   search = jasmine.createSpy('search').and.returnValue({});
   setSearch = jasmine.createSpy('setSearch');
   fullPageNavigationNeeded = jasmine.createSpy('Location.fullPageNavigationNeeded');
@@ -23,4 +23,3 @@ export class MockLocationService {
     return url.replace(/^\/+/, '').replace(/\/+(\?|#|$)/, '$1');
   }
 }
-
diff --git a/aio/tests/e2e/src/app.e2e-spec.ts b/aio/tests/e2e/src/app.e2e-spec.ts
index 50ac669b7c..92be250124 100644
--- a/aio/tests/e2e/src/app.e2e-spec.ts
+++ b/aio/tests/e2e/src/app.e2e-spec.ts
@@ -36,7 +36,7 @@ describe('site App', () => {
 
     // Test all headings (and sub-headings).
     expect(await navItemHeadings.count()).toBeGreaterThan(0);
-    await navItemHeadings.each(heading => testNavItemHeading(heading!, 1));
+    await navItemHeadings.each(heading => heading && testNavItemHeading(heading, 1));
 
     // Helpers
     async function expectToBeCollapsed(elementFinder: ElementFinder) {
@@ -63,7 +63,7 @@ describe('site App', () => {
       // Recursively test child-headings (while this heading is expanded).
       const nextLevel = level + 1;
       const childNavItemHeadings = page.getNavItemHeadings(children, nextLevel);
-      await childNavItemHeadings.each(childHeading => testNavItemHeading(childHeading!, nextLevel));
+      await childNavItemHeadings.each(childHeading => childHeading && testNavItemHeading(childHeading, nextLevel));
 
       // Ensure heading does not cause navigation when collapsing.
       await page.click(heading);
diff --git a/aio/tslint.json b/aio/tslint.json
index 26e5eaf064..1fd7816557 100644
--- a/aio/tslint.json
+++ b/aio/tslint.json
@@ -61,8 +61,7 @@
       true,
       "ignore-params"
     ],
-    // TODO(gkalpak): Fix the code and enable this to align with CLI. (Failures: 59)
-    // "no-non-null-assertion": true,
+    "no-non-null-assertion": true,
     "no-redundant-jsdoc": true,
     "no-switch-case-fall-through": true,
     "no-var-requires": false,