fix(platform-browser): Update types for TypeScript nullability support

Closes #15898

packages/platform-browser/src/dom/debug/by.ts

@@ -49,6 +49,6 @@ export class By {
    * {@example platform-browser/dom/debug/ts/by/by.ts region='by_directive'}
    */
   static directive(type: Type<any>): Predicate<DebugElement> {
-    return (debugElement) => debugElement.providerTokens.indexOf(type) !== -1;
+    return (debugElement) => debugElement.providerTokens !.indexOf(type) !== -1;
   }
 }

packages/platform-browser/src/dom/debug/ng_probe.ts

@@ -22,7 +22,7 @@ const CORE_TOKENS_GLOBAL_NAME = 'ng.coreTokens';
  * null if the given native element does not have an Angular view associated
  * with it.
  */
-export function inspectNativeElement(element: any): core.DebugNode {
+export function inspectNativeElement(element: any): core.DebugNode|null {
   return core.getDebugNode(element);
 }
 

packages/platform-browser/src/dom/dom_adapter.ts

@@ -8,7 +8,7 @@
 
 import {Type} from '@angular/core';
 
-let _DOM: DomAdapter = null;
+let _DOM: DomAdapter = null !;
 
 export function getDOM() {
   return _DOM;
@@ -32,7 +32,7 @@ export function setRootDomAdapter(adapter: DomAdapter) {
  * can introduce XSS risks.
  */
 export abstract class DomAdapter {
-  public resourceLoaderType: Type<any> = null;
+  public resourceLoaderType: Type<any> = null !;
   abstract hasProperty(element: any, name: string): boolean;
   abstract setProperty(el: Element, name: string, value: any): any;
   abstract getProperty(el: Element, name: string): any;
@@ -68,12 +68,12 @@ export abstract class DomAdapter {
   abstract getTemplateContent(el: any): any;
   abstract getOuterHTML(el: any): string;
   abstract nodeName(node: any): string;
-  abstract nodeValue(node: any): string;
+  abstract nodeValue(node: any): string|null;
   abstract type(node: any): string;
   abstract content(node: any): any;
-  abstract firstChild(el: any): Node;
-  abstract nextSibling(el: any): Node;
-  abstract parentElement(el: any): Node;
+  abstract firstChild(el: any): Node|null;
+  abstract nextSibling(el: any): Node|null;
+  abstract parentElement(el: any): Node|null;
   abstract childNodes(el: any): Node[];
   abstract childNodesAsList(el: any): Node[];
   abstract clearNodes(el: any): any;
@@ -85,7 +85,7 @@ export abstract class DomAdapter {
   abstract insertAllBefore(parent: any, ref: any, nodes: any): any;
   abstract insertAfter(parent: any, el: any, node: any): any;
   abstract setInnerHTML(el: any, value: any): any;
-  abstract getText(el: any): string;
+  abstract getText(el: any): string|null;
   abstract setText(el: any, value: string): any;
   abstract getValue(el: any): string;
   abstract setValue(el: any, value: string): any;
@@ -117,7 +117,7 @@ export abstract class DomAdapter {
   abstract attributeMap(element: any): Map<string, string>;
   abstract hasAttribute(element: any, attribute: string): boolean;
   abstract hasAttributeNS(element: any, ns: string, attribute: string): boolean;
-  abstract getAttribute(element: any, attribute: string): string;
+  abstract getAttribute(element: any, attribute: string): string|null;
   abstract getAttributeNS(element: any, ns: string, attribute: string): string;
   abstract setAttribute(element: any, name: string, value: string): any;
   abstract setAttributeNS(element: any, ns: string, name: string, value: string): any;
@@ -145,12 +145,12 @@ export abstract class DomAdapter {
   abstract getGlobalEventTarget(doc: Document, target: string): any;
   abstract getHistory(): History;
   abstract getLocation(): Location;
-  abstract getBaseHref(doc: Document): string;
+  abstract getBaseHref(doc: Document): string|null;
   abstract resetBaseElement(): void;
   abstract getUserAgent(): string;
   abstract setData(element: any, name: string, value: string): any;
   abstract getComputedStyle(element: any): any;
-  abstract getData(element: any, name: string): string;
+  abstract getData(element: any, name: string): string|null;
   abstract setGlobalVar(name: string, value: any): any;
   abstract supportsWebAnimation(): boolean;
   abstract performanceNow(): number;
@@ -159,6 +159,6 @@ export abstract class DomAdapter {
   abstract supportsAnimation(): boolean;
 
   abstract supportsCookies(): boolean;
-  abstract getCookie(name: string): string;
+  abstract getCookie(name: string): string|null;
   abstract setCookie(name: string, value: string): any;
 }

packages/platform-browser/src/dom/dom_renderer.ts

@@ -67,7 +67,7 @@ export class DomRendererFactory2 implements RendererFactory2 {
     this.defaultRenderer = new DefaultDomRenderer2(eventManager);
   };
 
-  createRenderer(element: any, type: RendererType2): Renderer2 {
+  createRenderer(element: any, type: RendererType2|null): Renderer2 {
     if (!element || !type) {
       return this.defaultRenderer;
     }

packages/platform-browser/src/dom/events/hammer_gestures.ts

@@ -59,8 +59,8 @@ const EVENT_NAMES = {
 export const HAMMER_GESTURE_CONFIG = new InjectionToken<HammerGestureConfig>('HammerGestureConfig');
 
 export interface HammerInstance {
-  on(eventName: string, callback: Function): void;
-  off(eventName: string, callback: Function): void;
+  on(eventName: string, callback?: Function): void;
+  off(eventName: string, callback?: Function): void;
 }
 
 /**

packages/platform-browser/src/dom/events/key_events.ts

@@ -31,7 +31,7 @@ export class KeyEventsPlugin extends EventManagerPlugin {
   supports(eventName: string): boolean { return KeyEventsPlugin.parseEventName(eventName) != null; }
 
   addEventListener(element: HTMLElement, eventName: string, handler: Function): Function {
-    const parsedEvent = KeyEventsPlugin.parseEventName(eventName);
+    const parsedEvent = KeyEventsPlugin.parseEventName(eventName) !;
 
     const outsideHandler =
         KeyEventsPlugin.eventCallback(parsedEvent['fullKey'], handler, this.manager.getZone());
@@ -41,7 +41,7 @@ export class KeyEventsPlugin extends EventManagerPlugin {
     });
   }
 
-  static parseEventName(eventName: string): {[key: string]: string} {
+  static parseEventName(eventName: string): {[key: string]: string}|null {
     const parts: string[] = eventName.toLowerCase().split('.');
 
     const domEventName = parts.shift();
@@ -49,7 +49,7 @@ export class KeyEventsPlugin extends EventManagerPlugin {
       return null;
     }
 
-    const key = KeyEventsPlugin._normalizeKey(parts.pop());
+    const key = KeyEventsPlugin._normalizeKey(parts.pop() !);
 
     let fullKey = '';
     MODIFIER_KEYS.forEach(modifierName => {