fix(core): Update types for TypeScript nullability support (#15472)

packages/core/testing/src/component_fixture.ts

@@ -42,15 +42,16 @@ export class ComponentFixture<T> {
 
   private _isStable: boolean = true;
   private _isDestroyed: boolean = false;
-  private _resolve: (result: any) => void;
-  private _promise: Promise<any> = null;
+  private _resolve: ((result: any) => void)|null = null;
+  private _promise: Promise<any>|null = null;
   private _onUnstableSubscription: any /** TODO #9100 */ = null;
   private _onStableSubscription: any /** TODO #9100 */ = null;
   private _onMicrotaskEmptySubscription: any /** TODO #9100 */ = null;
   private _onErrorSubscription: any /** TODO #9100 */ = null;
 
   constructor(
-      public componentRef: ComponentRef<T>, public ngZone: NgZone, private _autoDetect: boolean) {
+      public componentRef: ComponentRef<T>, public ngZone: NgZone|null,
+      private _autoDetect: boolean) {
     this.changeDetectorRef = componentRef.changeDetectorRef;
     this.elementRef = componentRef.location;
     this.debugElement = <DebugElement>getDebugNode(this.elementRef.nativeElement);
@@ -59,7 +60,7 @@ export class ComponentFixture<T> {
     this.componentRef = componentRef;
     this.ngZone = ngZone;
 
-    if (ngZone != null) {
+    if (ngZone) {
       this._onUnstableSubscription =
           ngZone.onUnstable.subscribe({next: () => { this._isStable = false; }});
       this._onMicrotaskEmptySubscription = ngZone.onMicrotaskEmpty.subscribe({
@@ -82,7 +83,7 @@ export class ComponentFixture<T> {
             scheduleMicroTask(() => {
               if (!this.ngZone.hasPendingMacrotasks) {
                 if (this._promise !== null) {
-                  this._resolve(true);
+                  this._resolve !(true);
                   this._resolve = null;
                   this._promise = null;
                 }

packages/core/testing/src/test_bed.ts

@@ -135,7 +135,7 @@ export class TestBed implements Injector {
   }
 
   static overrideTemplate(component: Type<any>, template: string): typeof TestBed {
-    getTestBed().overrideComponent(component, {set: {template, templateUrl: null}});
+    getTestBed().overrideComponent(component, {set: {template, templateUrl: null !}});
     return TestBed;
   }
 
@@ -149,9 +149,9 @@ export class TestBed implements Injector {
 
   private _instantiated: boolean = false;
 
-  private _compiler: TestingCompiler = null;
-  private _moduleRef: NgModuleRef<any> = null;
-  private _moduleWithComponentFactories: ModuleWithComponentFactories<any> = null;
+  private _compiler: TestingCompiler = null !;
+  private _moduleRef: NgModuleRef<any> = null !;
+  private _moduleWithComponentFactories: ModuleWithComponentFactories<any> = null !;
 
   private _compilerOptions: CompilerOptions[] = [];
 
@@ -194,19 +194,19 @@ export class TestBed implements Injector {
    */
   resetTestEnvironment() {
     this.resetTestingModule();
-    this.platform = null;
-    this.ngModule = null;
+    this.platform = null !;
+    this.ngModule = null !;
   }
 
   resetTestingModule() {
-    this._compiler = null;
+    this._compiler = null !;
     this._moduleOverrides = [];
     this._componentOverrides = [];
     this._directiveOverrides = [];
     this._pipeOverrides = [];
 
-    this._moduleRef = null;
-    this._moduleWithComponentFactories = null;
+    this._moduleRef = null !;
+    this._moduleWithComponentFactories = null !;
     this._compilerOptions = [];
     this._providers = [];
     this._declarations = [];
@@ -223,9 +223,9 @@ export class TestBed implements Injector {
     this._activeFixtures = [];
   }
 
-  platform: PlatformRef = null;
+  platform: PlatformRef = null !;
 
-  ngModule: Type<any>|Type<any>[] = null;
+  ngModule: Type<any>|Type<any>[] = null !;
 
   configureCompiler(config: {providers?: any[], useJit?: boolean}) {
     this._assertNotInstantiated('TestBed.configureCompiler', 'configure the compiler');
@@ -383,7 +383,7 @@ export class TestBed implements Injector {
   }
 }
 
-let _testBed: TestBed = null;
+let _testBed: TestBed = null !;
 
 /**
  * @experimental
@@ -463,7 +463,7 @@ export class InjectSetupWrapper {
  */
 export function withModule(moduleDef: TestModuleMetadata): InjectSetupWrapper;
 export function withModule(moduleDef: TestModuleMetadata, fn: Function): () => any;
-export function withModule(moduleDef: TestModuleMetadata, fn: Function = null): (() => any)|
+export function withModule(moduleDef: TestModuleMetadata, fn?: Function | null): (() => any)|
     InjectSetupWrapper {
   if (fn) {
     // Not using an arrow function to preserve context passed from call site

packages/core/testing/src/testing_internal.ts

@@ -62,7 +62,7 @@ jsmBeforeEach(() => { testBed.resetTestingModule(); });
 
 function _describe(jsmFn: Function, ...args: any[]) {
   const parentRunner = runnerStack.length === 0 ? null : runnerStack[runnerStack.length - 1];
-  const runner = new BeforeEachRunner(parentRunner);
+  const runner = new BeforeEachRunner(parentRunner !);
   runnerStack.push(runner);
   const suite = jsmFn(...args);
   runnerStack.pop();