Improve Angular cheatsheet

frontend/angular.js

@@ -4,343 +4,397 @@
  * STYLE GUIDE: https://angular.io/guide/styleguide
  * ******************************************************************************************* */
 
+
 ```
 npm install --save @angular/cli       // declarative and flexible JavaScript framework for building UI
 ng serve                              // serve the app
 ng build                              // build the release
 ```
 
+
 /* *******************************************************************************************
- * Bootstrapping 
+ * BOOSTRAPPING
+ * https://angular.io/guide/bootstrapping
  * ******************************************************************************************* */
 
+
 import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
 
-platformBrowserDynamic().bootstrapModule(AppModule); 
 // Bootstraps the app, using the root component from the specified NgModule.
+platformBrowserDynamic().bootstrapModule(AppModule); 
+
 
 /* *******************************************************************************************
- * NgModules 
+ * NG MODULES
+ * https://angular.io/guide/ngmodules
  * ******************************************************************************************* */
+
+
 import { NgModule } from '@angular/core';
 
-@NgModule({ declarations: ..., imports: ...,
+@NgModule({
-exports: ..., providers: ..., bootstrap: ...})
+  declarations: ...,
-class MyModule {} 
+  imports: ...,
+  exports: ...,
+  providers: ...,
+  bootstrap: ...
+})
+
 // Defines a module that contains components, directives, pipes, and providers.
+class MyModule {} 
 
-declarations: [MyRedComponent, MyBlueComponent, MyDatePipe] 
 // List of components, directives, and pipes that belong to this module.
+declarations: [MyRedComponent, MyBlueComponent, MyDatePipe] 
 
-imports: [BrowserModule, SomeOtherModule] 
 // List of modules to import into this module. Everything from the imported modules is available to declarations of this module.
+imports: [BrowserModule, SomeOtherModule] 
 
-exports: [MyRedComponent, MyDatePipe] 
 // List of components, directives, and pipes visible to modules that import this module.
+exports: [MyRedComponent, MyDatePipe] 
 
-providers: [MyService, { provide: ... }]  
 // List of dependency injection providers visible both to the contents of this module and to importers of this module.
+providers: [MyService, { provide: ... }]  
 
-bootstrap: [MyAppComponent] 
 // List of components to bootstrap when this module is bootstrapped.
+bootstrap: [MyAppComponent] 
 
 
 /* *******************************************************************************************
- * Template syntax 
+ * TEMPLATE SYNTAX
+ * https://angular.io/guide/template-syntax
  * ******************************************************************************************* */
 
-// <input [value]="firstName"> 
+
 // Binds property value to the result of expression firstName.
+// <input [value]="firstName"> 
 
-// <div [attr.role]="myAriaRole">  
 // Binds attribute role to the result of expression myAriaRole.
+// <div [attr.role]="myAriaRole">  
 
-// <div [class.extra-sparkle]="isDelightful">  
 // Binds the presence of the CSS class extra-sparkle on the element to the truthiness of the expression isDelightful.
+// <div [class.extra-sparkle]="isDelightful">  
 
-// <div [style.width.px]="mySize"> 
 // Binds style property width to the result of expression mySize in pixels. Units are optional.
+// <div [style.width.px]="mySize"> 
 
-// <button (click)="readRainbow($event)">  
 // Calls method readRainbow when a click event is triggered on this button element (or its children) and passes in the event object.
+// <button (click)="readRainbow($event)">  
 
-// <div title="Hello {{ponyName}}">  
 // Binds a property to an interpolated string, for example, "Hello Seabiscuit". Equivalent to: <div [title]="'Hello ' + ponyName">
+// <div title="Hello {{ponyName}}">  
 
-// <p>Hello {{ponyName}}</p> 
 // Binds text content to an interpolated string, for example, "Hello Seabiscuit".
+// <p>Hello {{ponyName}}</p> 
 
-// <my-cmp [(title)]="name"> 
 // Sets up two-way data binding. Equivalent to: <my-cmp [title]="name" (titleChange)="name=$event">
+// <my-cmp [(title)]="name"> 
 
+// Creates a local variable movieplayer that provides access to the video element instance in data-binding and event-binding expressions in the current template.
 // <video #movieplayer ...>
 // <button (click)="movieplayer.play()">
 // </video>  
-// Creates a local variable movieplayer that provides access to the video element instance in data-binding and event-binding expressions in the current template.
 
-// <p *myUnless="myExpression">...</p> 
 // The * symbol turns the current element into an embedded template. Equivalent to: <ng-template [myUnless]="myExpression"><p>...</p></ng-template>
+// <p *myUnless="myExpression">...</p> 
 
-// <p>Card No.: {{cardNumber | myCardNumberFormatter}}</p> 
 // Transforms the current value of expression cardNumber via the pipe called myCardNumberFormatter.
+// <p>Card No.: {{cardNumber | myCardNumberFormatter}}</p> 
 
-// <p>Employer: {{employer?.companyName}}</p>  
 // The safe navigation operator (?) means that the employer field is optional and if undefined, the rest of the expression should be ignored.
+// <p>Employer: {{employer?.companyName}}</p>  
 
-// <svg:rect x="0" y="0" width="100" height="100"/>  
 // An SVG snippet template needs an svg: prefix on its root element to disambiguate the SVG element from an HTML component.
+// <svg:rect x="0" y="0" width="100" height="100"/>  
 
+// An <svg> root element is detected as an SVG element automatically, without the prefix.
 // <svg>
 // <rect x="0" y="0" width="100" height="100"/>
 // </svg>  
-// An <svg> root element is detected as an SVG element automatically, without the prefix.
+
 
 /* *******************************************************************************************
- * Built-in directives
+ * BUILT-IN DIRECTIVES
+ * https://angular.io/guide/attribute-directives
  * ******************************************************************************************* */
+
+
 import { CommonModule } from '@angular/common';
 
-// // <section *ngIf="showSection"> 
+// Removes or recreates a portion of the DOM tree based on the showSection expression.
-// // Removes or recreates a portion of the DOM tree based on the showSection expression.
+// <section *ngIf="showSection"> 
 
-// <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.
+// <li *ngFor="let item of list">  
 
+// Conditionally swaps the contents of the div by selecting one of the embedded templates based on the current value of conditionExpression.
 // <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 conditionExpression.
 
-// <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 [ngClass]="{'active': isActive, 'disabled': isDisabled}">  
 
+// 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.
 // <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
+ * FORMS
+ * https://angular.io/guide/forms
  * ******************************************************************************************* */
 
+
 import { FormsModule } from '@angular/forms';
 
-// <input [(ngModel)]="userName">  
 // Provides two-way data-binding, parsing, and validation for form controls.
+// <input [(ngModel)]="userName">  
+
 
 /* *******************************************************************************************
- * Class decorators
+ * CLASS DECORATORS
  * ******************************************************************************************* */
 
+
 import { Directive, ... } from '@angular/core';
 
+// Declares that a class is a component and provides metadata about the component.
 @Component({...})
 class MyComponent() {}  
-// Declares that a class is a component and provides metadata about the component.
 
+// Declares that a class is a directive and provides metadata about the directive.
 @Directive({...})
 class MyDirective() {}  
-// Declares that a class is a directive and provides metadata about the directive.
 
+// Declares that a class is a pipe and provides metadata about the pipe.
 @Pipe({...})
 class MyPipe() {} 
-// Declares that a class is a pipe and provides metadata about the pipe.
 
+// Declares that a class has dependencies that should be injected into the constructor when the dependency injector is creating an instance of this class.
 @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
+ * DIRECTIVE CONFIGURATION
  * ******************************************************************************************* */
 
+
 @Directive({ property1: value1, ... })
 
-selector: '.cool-button:not(a)' 
 // Specifies a CSS selector that identifies this directive within a template. Supported selectors include element, [attribute], .class, and :not().
+selector: '.cool-button:not(a)' 
 
 // Does not support parent-child relationship selectors.
 
-providers: [MyService, { provide: ... }]  
 // List of dependency injection providers for this directive and its children.
+providers: [MyService, { provide: ... }]  
+
 
 /* *******************************************************************************************
- * Component configuration
+ * COMPONENT CONFIGURATION
+ * https://angular.io/api/core/Component
  * ******************************************************************************************* */
 
+
 @Component extends @Directive, so the @Directive configuration applies to components as well
 
-moduleId: module.id 
 // If set, the templateUrl and styleUrl are resolved relative to the component.
+moduleId: module.id 
 
-viewProviders: [MyService, { provide: ... }]  
 // List of dependency injection providers scoped to this component's view.
+viewProviders: [MyService, { provide: ... }]  
 
+// Inline template or external template URL of the component's view.
 template: 'Hello {{name}}'
 templateUrl: 'my-component.html'  
-// Inline template or external template URL of the component's view.
 
+// List of inline CSS styles or external stylesheet URLs for styling 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
+ * CLASS FIELD DECORATORS FOR DIRECTIVES AND COMPONENTS
  * ******************************************************************************************* */
 
+
 import { Input, ... } from '@angular/core';
 
-@Input() myProperty;  
 // Declares an input property that you can update via property binding (example: <my-cmp [myProperty]="someExpression">).
+@Input() myProperty;  
 
-@Output() myEvent = new EventEmitter(); 
 // Declares an output property that fires events that you can subscribe to with an event binding (example: <my-cmp (myEvent)="doSomething()">).
+@Output() myEvent = new EventEmitter(); 
 
-@HostBinding('class.valid') isValid;  
 // Binds a host element property (here, the CSS class valid) to a directive/component property (isValid).
+@HostBinding('class.valid') isValid;  
 
-@HostListener('click', ['$event']) onClick(e) {...} 
 // Subscribes to a host element event (click) with a directive/component method (onClick), optionally passing an argument ($event).
+@HostListener('click', ['$event']) onClick(e) {...} 
 
-@ContentChild(myPredicate) myChildComponent;  
 // Binds the first result of the component content query (myPredicate) to a property (myChildComponent) of the class.
+@ContentChild(myPredicate) myChildComponent;  
 
-@ContentChildren(myPredicate) myChildComponents;  
 // Binds the results of the component content query (myPredicate) to a property (myChildComponents) of the class.
+@ContentChildren(myPredicate) myChildComponents;  
 
-@ViewChild(myPredicate) myChildComponent; 
 // Binds the first result of the component view query (myPredicate) to a property (myChildComponent) of the class. Not available for directives.
+@ViewChild(myPredicate) myChildComponent; 
 
-@ViewChildren(myPredicate) myChildComponents; 
 // Binds the results of the component view query (myPredicate) to a property (myChildComponents) of the class. Not available for directives.
+@ViewChildren(myPredicate) myChildComponents; 
+
 
 /* *******************************************************************************************
- * Directive and component change detection and lifecycle hooks
+ * 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.
+constructor(myService: MyService, ...) { ... }  
 
-ngOnChanges(changeRecord) { ... } 
 // Called after every change to input properties and before processing content or child views.
+ngOnChanges(changeRecord) { ... } 
 
-ngOnInit() { ... }  
 // Called after the constructor, initializing input properties, and the first call to ngOnChanges.
+ngOnInit() { ... }  
 
-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.
+ngDoCheck() { ... } 
 
-ngAfterContentInit() { ... }  
 // Called after ngOnInit when the component's or directive's content has been initialized.
+ngAfterContentInit() { ... }  
 
-ngAfterContentChecked() { ... } 
 // Called after every check of the component's or directive's content.
+ngAfterContentChecked() { ... } 
 
-ngAfterViewInit() { ... } 
 // Called after ngAfterContentInit when the component's views and child views / the view that a directive is in has been initialized.
+ngAfterViewInit() { ... } 
 
-ngAfterViewChecked() { ... }  
 // Called after every check of the component's views and child views / the view that a directive is in.
+ngAfterViewChecked() { ... }  
 
-ngOnDestroy() { ... } 
 // Called once, before the instance is destroyed.
+ngOnDestroy() { ... } 
+
 
 /* *******************************************************************************************
- * Dependency injection configuration
+ * DEPENDENCY INJECTION CONFIGURATION
+ * https://angular.io/guide/dependency-injection
  * ******************************************************************************************* */
 
-{ provide: MyService, useClass: MyMockService } 
+
 // Sets or overrides the provider for MyService to the MyMockService class.
+{ provide: MyService, useClass: MyMockService } 
 
-{ provide: MyService, useFactory: myFactory } 
 // Sets or overrides the provider for MyService to the myFactory factory function.
+{ provide: MyService, useFactory: myFactory } 
 
-{ provide: MyValue, useValue: 41 }  
 // Sets or overrides the provider for MyValue to the value 41.
+{ provide: MyValue, useValue: 41 }  
+
 
 /* *******************************************************************************************
- * Routing and navigation
+ * ROUTING AND NAVIGATION
+ * https://angular.io/guide/router
  * ******************************************************************************************* */
 
+
 import { Routes, RouterModule, ... } from '@angular/router';
 
 const routes: Routes = [
-{ path: '', component: HomeComponent },
+  { path: '', component: HomeComponent },
-{ path: 'path/:routeParam', component: MyComponent },
+  { path: 'path/:routeParam', component: MyComponent },
-{ path: 'staticPath', component: ... },
+  { path: 'staticPath', component: ... },
-{ path: '**', component: ... },
+  { path: '**', component: ... },
-{ path: 'oldPath', redirectTo: '/staticPath' },
+  { path: 'oldPath', redirectTo: '/staticPath' },
-{ path: ..., component: ..., data: { message: 'Custom' } }
+  { 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.
+const routing = RouterModule.forRoot(routes); 
 
+// Marks the location to load the component of the active route.
 // <router-outlet></router-outlet>
 // <router-outlet name="aux"></router-outlet>
-// Marks the location to load the component of the active route.
-
 
+// 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 / prefix; for a child route, use the ./prefix; for a sibling or parent, use the ../ prefix.
 // <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 / prefix; for a child route, use the ./prefix; for a sibling or parent, use the ../ prefix.
 
-// <a [routerLink]="[ '/path' ]" routerLinkActive="active">  
 // The provided classes are added to the element when the routerLink becomes the current active route.
+// <a [routerLink]="[ '/path' ]" routerLinkActive="active">  
 
 class CanActivateGuard implements CanActivate {
-canActivate(
+  canActivate(
-route: ActivatedRouteSnapshot,
+    route: ActivatedRouteSnapshot,
-state: RouterStateSnapshot
+    state: RouterStateSnapshot
-): Observable<boolean>|Promise<boolean>|boolean { ... }
+  ): 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.
+{
+  path: ...,
+  canActivate: [CanActivateGuard]
+}  
 
 class CanDeactivateGuard implements CanDeactivate<T> {
-canDeactivate(
+  canDeactivate(
-component: T,
+    component: T,
-route: ActivatedRouteSnapshot,
+    route: ActivatedRouteSnapshot,
-state: RouterStateSnapshot
+    state: RouterStateSnapshot
-): Observable<boolean>|Promise<boolean>|boolean { ... }
+  ): 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.
+{
+  path: ...,
+  canDeactivate: [CanDeactivateGuard]
+}
 
 class CanActivateChildGuard implements CanActivateChild {
-canActivateChild(
+  canActivateChild(
-route: ActivatedRouteSnapshot,
+    route: ActivatedRouteSnapshot,
-state: RouterStateSnapshot
+    state: RouterStateSnapshot
-): Observable<boolean>|Promise<boolean>|boolean { ... }
+  ): 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.
+{
+  path: ...,
+  canActivateChild: [CanActivateGuard],
+  children: ...
+}
 
 class ResolveGuard implements Resolve<T> {
-resolve(
+  resolve(
-route: ActivatedRouteSnapshot,
+    route: ActivatedRouteSnapshot,
-state: RouterStateSnapshot
+    state: RouterStateSnapshot
-): Observable<any>|Promise<any>|any { ... }
+  ): 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.
+{
+  path: ...,
+  resolve: [ResolveGuard]
+}
 
 class CanLoadGuard implements CanLoad {
-canLoad(
+  canLoad(
-route: Route
+    route: Route
-): Observable<boolean>|Promise<boolean>|boolean { ... }
+  ): 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.
+{
+  path: ...,
+  canLoad: [CanLoadGuard],
+  loadChildren: ...
+}