fix: Update types for TypeScript nullability support in examples

packages/examples/common/ngIf/ts/module.ts

@@ -57,13 +57,13 @@ class NgIfElse {
 `
 })
 class NgIfThenElse implements OnInit {
-  thenBlock: TemplateRef<any> = null;
+  thenBlock: TemplateRef<any>|null = null;
   show: boolean = true;
 
   @ViewChild('primaryBlock')
-  primaryBlock: TemplateRef<any> = null;
+  primaryBlock: TemplateRef<any>|null = null;
   @ViewChild('secondaryBlock')
-  secondaryBlock: TemplateRef<any> = null;
+  secondaryBlock: TemplateRef<any>|null = null;
 
   switchPrimary() {
     this.thenBlock = this.thenBlock === this.primaryBlock ? this.secondaryBlock : this.primaryBlock;

packages/examples/common/pipes/ts/async_pipe.ts

@@ -20,10 +20,10 @@ import {Subscriber} from 'rxjs/Subscriber';
   </div>`
 })
 export class AsyncPromisePipeComponent {
-  greeting: Promise<string> = null;
+  greeting: Promise<string>|null = null;
   arrived: boolean = false;
 
-  private resolve: Function = null;
+  private resolve: Function|null = null;
 
   constructor() { this.reset(); }
 
@@ -36,7 +36,7 @@ export class AsyncPromisePipeComponent {
     if (this.arrived) {
       this.reset();
     } else {
-      this.resolve('hi there!');
+      this.resolve !('hi there!');
       this.arrived = true;
     }
   }

packages/examples/core/debug/ts/debug_element/debug_element.ts

@@ -8,7 +8,7 @@
 
 import {DebugElement} from '@angular/core';
 
-let debugElement: DebugElement;
+let debugElement: DebugElement = undefined !;
 let predicate: any;
 
 // #docregion scope_all

packages/examples/core/di/ts/metadata_spec.ts

@@ -171,7 +171,7 @@ export function main() {
           declarations: [App, ParentCmp, ChildDirective],
         });
 
-        let cmp: ComponentFixture<App>;
+        let cmp: ComponentFixture<App> = undefined !;
         expect(() => cmp = TestBed.createComponent(App)).not.toThrow();
 
         expect(cmp.debugElement.children[0].children[0].injector.get(ChildDirective).logs).toEqual([

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

@@ -9,7 +9,7 @@
 import {DebugElement} from '@angular/core';
 import {By} from '@angular/platform-browser';
 
-let debugElement: DebugElement;
+let debugElement: DebugElement = undefined !;
 class MyDirective {}
 
 // #docregion by_all

packages/examples/tsconfig-build.json

@@ -5,6 +5,7 @@
     "stripInternal": true,
     "experimentalDecorators": true,
     "noImplicitAny": true,
+    "strictNullChecks": true,
     "emitDecoratorMetadata": true,
     "module": "commonjs",
     "moduleResolution": "node",