Cheat Sheet
| Bootstrapping | 
 
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|---|---|
platformBrowserDynamic().bootstrapModule(AppModule); |  
 Bootstraps the app, using the root component from the specified   |  
| NgModules | 
 
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|---|---|
@NgModule({ declarations: ..., imports: ...,     exports: ..., providers: ..., bootstrap: ...})class MyModule {} |  
 Defines a module that contains components, directives, pipes, and providers.  |  
declarations: [MyRedComponent, MyBlueComponent, MyDatePipe] |  
 List of components, directives, and pipes that belong to this module.  |  
imports: [BrowserModule, SomeOtherModule] |  
 List of modules to import into this module. Everything from the imported modules is available to   |  
exports: [MyRedComponent, MyDatePipe] |  
 List of components, directives, and pipes visible to modules that import this module.  |  
providers: [MyService, { provide: ... }] |  
 List of dependency injection providers visible both to the contents of this module and to importers of this module.  |  
entryComponents: [SomeComponent, OtherComponent] |  List of components not referenced in any reachable template, for example dynamically created from code.  |  
bootstrap: [MyAppComponent] |  
 List of components to bootstrap when this module is bootstrapped.  |  
| Template syntax | |
|---|---|
<input [value]="firstName"> |  
 Binds property   |  
<div [attr.role]="myAriaRole"> |  
 Binds attribute   |  
<div [class.extra-sparkle]="isDelightful"> |  
 Binds the presence of the CSS class   |  
<div [style.width.px]="mySize"> |  
 Binds style property   |  
<button (click)="readRainbow($event)"> |  
 Calls method   |  
<div title="Hello {{ponyName}}"> |  
 Binds a property to an interpolated string, for example, "Hello Seabiscuit". Equivalent to:   |  
<p>Hello {{ponyName}}</p> |  
 Binds text content to an interpolated string, for example, "Hello Seabiscuit".  |  
<my-cmp [(title)]="name"> |  
 Sets up two-way data binding. Equivalent to:   |  
<video #movieplayer ...>  <button (click)="movieplayer.play()"></video> |  
 Creates a local variable   |  
<p *myUnless="myExpression">...</p> |  
 The   |  
<p>Card No.: {{cardNumber | myCardNumberFormatter}}</p> |  
 Transforms the current value of expression   |  
<p>Employer: {{employer?.companyName}}</p> |  
 The safe navigation operator (  |  
<svg:rect x="0" y="0" width="100" height="100"/> |  
 An SVG snippet template needs an   |  
<svg>  <rect x="0" y="0" width="100" height="100"/></svg> |  
 An   |  
| Built-in directives | 
 
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|---|---|
<section *ngIf="showSection"> |  
 Removes or recreates a portion of the DOM tree based on the   |  
<li *ngFor="let item of list"> |  
 Turns the li element and its contents into a template, and uses that to instantiate a view for each item in list.  |  
<div [ngSwitch]="conditionExpression">  <ng-template [ngSwitchCase]="case1Exp">...</ng-template>  <ng-template ngSwitchCase="case2LiteralString">...</ng-template>  <ng-template ngSwitchDefault>...</ng-template></div> |  
 Conditionally swaps the contents of the div by selecting one of the embedded templates based on the current value of   |  
<div [ngClass]="{'active': isActive, 'disabled': isDisabled}"> |  
 Binds the presence of CSS classes on the element to the truthiness of the associated map values. The right-hand expression should return {class-name: true/false} map.  |  
<div [ngStyle]="{'property': 'value'}"><div [ngStyle]="dynamicStyles()">
 |  
 Allows you to assign styles to an HTML element using CSS. You can use CSS directly, as in the first example, or you can call a method from the component.  |  
| Forms | 
 
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|---|---|
<input [(ngModel)]="userName"> |  
 Provides two-way data-binding, parsing, and validation for form controls.  |  
| Class decorators | 
 
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|---|---|
@Component({...})class MyComponent() {} |  
 Declares that a class is a component and provides metadata about the component.  |  
@Directive({...})class MyDirective() {} |  
 Declares that a class is a directive and provides metadata about the directive.  |  
@Pipe({...})class MyPipe() {} |  
 Declares that a class is a pipe and provides metadata about the pipe.  |  
@Injectable()class MyService() {} |  
 Declares that a class has dependencies that should be injected into the constructor when the dependency injector is creating an instance of this class.  |  
| Directive configuration | 
 
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|---|---|
selector: '.cool-button:not(a)' |  
 Specifies a CSS selector that identifies this directive within a template. Supported selectors include  Does not support parent-child relationship selectors.  |  
providers: [MyService, { provide: ... }] |  
 List of dependency injection providers for this directive and its children.  |  
| Component configuration | 
    |  
|---|---|
moduleId: module.id |  
 If set, the   |  
viewProviders: [MyService, { provide: ... }] |  
 List of dependency injection providers scoped to this component's view.  |  
template: 'Hello {{name}}'templateUrl: 'my-component.html' |  
 Inline template or external template URL of the component's view.  |  
styles: ['.primary {color: red}']styleUrls: ['my-component.css'] |  
 List of inline CSS styles or external stylesheet URLs for styling the component’s view.  |  
| Class field decorators for directives and components | 
 
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|---|---|
@Input() myProperty; |  
 Declares an input property that you can update via property binding (example:   |  
@Output() myEvent = new EventEmitter(); |  
 Declares an output property that fires events that you can subscribe to with an event binding (example:   |  
@HostBinding('class.valid') isValid; |  
 Binds a host element property (here, the CSS class   |  
@HostListener('click', ['$event']) onClick(e) {...} |  
 Subscribes to a host element event (  |  
@ContentChild(myPredicate) myChildComponent; |  
 Binds the first result of the component content query (  |  
@ContentChildren(myPredicate) myChildComponents; |  
 Binds the results of the component content query (  |  
@ViewChild(myPredicate) myChildComponent; |  
 Binds the first result of the component view query (  |  
@ViewChildren(myPredicate) myChildComponents; |  
 Binds the results of the component view query (  |  
| Directive and component change detection and lifecycle hooks | 
 (implemented as class methods)  |  
|---|---|
constructor(myService: MyService, ...) { ... } |  
 Called before any other lifecycle hook. Use it to inject dependencies, but avoid any serious work here.  |  
ngOnChanges(changeRecord) { ... } |  
 Called after every change to input properties and before processing content or child views.  |  
ngOnInit() { ... } |  
 Called after the constructor, initializing input properties, and the first call to   |  
ngDoCheck() { ... } |  
 Called every time that the input properties of a component or a directive are checked. Use it to extend change detection by performing a custom check.  |  
ngAfterContentInit() { ... } |  
 Called after   |  
ngAfterContentChecked() { ... } |  
 Called after every check of the component's or directive's content.  |  
ngAfterViewInit() { ... } |  
 Called after   |  
ngAfterViewChecked() { ... } |  
 Called after every check of the component's views and child views / the view that a directive is in.  |  
ngOnDestroy() { ... } |  
 Called once, before the instance is destroyed.  |  
| Dependency injection configuration | |
|---|---|
{ provide: MyService, useClass: MyMockService } |  
 Sets or overrides the provider for   |  
{ provide: MyService, useFactory: myFactory } |  
 Sets or overrides the provider for   |  
{ provide: MyValue, useValue: 41 } |  
 Sets or overrides the provider for   |  
| Routing and navigation | 
 
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|---|---|
const routes: Routes = [  { path: '', component: HomeComponent },  { path: 'path/:routeParam', component: MyComponent },  { path: 'staticPath', component: ... },  { path: '**', component: ... },  { path: 'oldPath', redirectTo: '/staticPath' },  { path: ..., component: ..., data: { message: 'Custom' } }]);const routing = RouterModule.forRoot(routes); |  
 Configures routes for the application. Supports static, parameterized, redirect, and wildcard routes. Also supports custom route data and resolve.  |  
<router-outlet></router-outlet><router-outlet name="aux"></router-outlet> |  
 Marks the location to load the component of the active route.  |  
<a routerLink="/path"><a [routerLink]="[ '/path', routeParam ]"><a [routerLink]="[ '/path', { matrixParam: 'value' } ]"><a [routerLink]="[ '/path' ]" [queryParams]="{ page: 1 }"><a [routerLink]="[ '/path' ]" fragment="anchor"> |  
 Creates a link to a different view based on a route instruction consisting of a route path, required and optional parameters, query parameters, and a fragment. To navigate to a root route, use the   |  
<a [routerLink]="[ '/path' ]" routerLinkActive="active"> |  
 The provided classes are added to the element when the   |  
class CanActivateGuard implements CanActivate {    canActivate(      route: ActivatedRouteSnapshot,      state: RouterStateSnapshot    ): Observable<boolean>|Promise<boolean>|boolean { ... }}{ path: ..., canActivate: [CanActivateGuard] } |  
 An interface for defining a class that the router should call first to determine if it should activate this component. Should return a boolean or an Observable/Promise that resolves to a boolean.  |  
class CanDeactivateGuard implements CanDeactivate<T> {    canDeactivate(      component: T,      route: ActivatedRouteSnapshot,      state: RouterStateSnapshot    ): Observable<boolean>|Promise<boolean>|boolean { ... }}{ path: ..., canDeactivate: [CanDeactivateGuard] } |  
 An interface for defining a class that the router should call first to determine if it should deactivate this component after a navigation. Should return a boolean or an Observable/Promise that resolves to a boolean.  |  
class CanActivateChildGuard implements CanActivateChild {    canActivateChild(      route: ActivatedRouteSnapshot,      state: RouterStateSnapshot    ): Observable<boolean>|Promise<boolean>|boolean { ... }}{ path: ..., canActivateChild: [CanActivateGuard],    children: ... } |  
 An interface for defining a class that the router should call first to determine if it should activate the child route. Should return a boolean or an Observable/Promise that resolves to a boolean.  |  
class ResolveGuard implements Resolve<T> {    resolve(      route: ActivatedRouteSnapshot,      state: RouterStateSnapshot    ): Observable<any>|Promise<any>|any { ... }}{ path: ..., resolve: [ResolveGuard] } |  
 An interface for defining a class that the router should call first to resolve route data before rendering the route. Should return a value or an Observable/Promise that resolves to a value.  |  
class CanLoadGuard implements CanLoad {    canLoad(      route: Route    ): Observable<boolean>|Promise<boolean>|boolean { ... }}{ path: ..., canLoad: [CanLoadGuard], loadChildren: ... } |  
 An interface for defining a class that the router should call first to check if the lazy loaded module should be loaded. Should return a boolean or an Observable/Promise that resolves to a boolean.  |  
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