awesome-cheatsheets/frontend/angular.js

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/* *******************************************************************************************
* ANGULAR (2+) CHEATSHEET
* BASED ON https://angular.io/guide/cheatsheet
* DOCUMENTATION: https://angular.io/docs
* STYLE GUIDE: https://angular.io/guide/styleguide
* ******************************************************************************************* */
```
npm install --save @angular/cli // install command line interface (CLI) for Angular apps
ng serve // serve the app
ng build // build the release
```
/* *******************************************************************************************
* BOOSTRAPPING
* https://angular.io/guide/bootstrapping
* ******************************************************************************************* */
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
// Bootstraps the app, using the root component from the specified NgModule.
platformBrowserDynamic().bootstrapModule(AppModule);
/* *******************************************************************************************
* NG MODULES
* https://angular.io/guide/ngmodules
* ******************************************************************************************* */
import { NgModule } from '@angular/core';
@NgModule({
declarations: ...,
imports: ...,
exports: ...,
providers: ...,
bootstrap: ...
})
// Defines a module that contains components, directives, pipes, and providers.
class MyModule {}
// List of components, directives, and pipes that belong to this module.
declarations: [MyRedComponent, MyBlueComponent, MyDatePipe]
// List of modules to import into this module. Everything from the imported modules is available
// to declarations of this module.
imports: [BrowserModule, SomeOtherModule]
// List of components, directives, and pipes visible to modules that import this module.
exports: [MyRedComponent, MyDatePipe]
// List of dependency injection providers visible both to the contents of this module and to
// importers of this module.
providers: [MyService, { provide: ... }]
// List of components to bootstrap when this module is bootstrapped.
bootstrap: [MyAppComponent]
/* *******************************************************************************************
* TEMPLATE SYNTAX
* https://angular.io/guide/template-syntax
* ******************************************************************************************* */
// Binds property value to the result of expression firstName.
// <input [value]="firstName">
// Binds attribute role to the result of expression myAriaRole.
// <div [attr.role]="myAriaRole">
// Binds the presence of the CSS class extra-sparkle on the element to the truthiness of the
// expression isDelightful.
// <div [class.extra-sparkle]="isDelightful">
// Binds style property width to the result of expression mySize in pixels. Units are optional.
// <div [style.width.px]="mySize">
// 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($event)">
// Binds a property to an interpolated string, for example, "Hello Seabiscuit".
// Equivalent to: <div [title]="'Hello ' + ponyName">
// <div title="Hello {{ponyName}}">
// Binds text content to an interpolated string, for example, "Hello Seabiscuit".
// <p>Hello {{ponyName}}</p>
// Sets up two-way data binding. Equivalent to: <my-cmp [title]="name" (titleChange)="name=$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>
// The * symbol turns the current element into an embedded template.
// Equivalent to: <ng-template [myUnless]="myExpression"><p>...</p></ng-template>
// <p *myUnless="myExpression">...</p>
// Transforms the current value of expression cardNumber via the pipe called myCardNumberFormatter.
// <p>Card No.: {{cardNumber | myCardNumberFormatter}}</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>
// 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>
/* *******************************************************************************************
* BUILT-IN DIRECTIVES
* https://angular.io/guide/attribute-directives
* ******************************************************************************************* */
import { CommonModule } from '@angular/common';
// Removes or recreates a portion of the DOM tree based on the showSection expression.
// <section *ngIf="showSection">
// 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>
// 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()">
/* *******************************************************************************************
* FORMS
* https://angular.io/guide/forms
* ******************************************************************************************* */
import { FormsModule } from '@angular/forms';
// Provides two-way data-binding, parsing, and validation for form controls.
// <input [(ngModel)]="userName">
/* *******************************************************************************************
* 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 directive and provides metadata about the directive.
@Directive({...})
class MyDirective() {}
// Declares that a class is a pipe and provides metadata about the pipe.
@Pipe({...})
class MyPipe() {}
// Declares that a class can be injected into the constructor of another class
// by the dependency injector.
@Injectable()
class MyService() {}
/* *******************************************************************************************
* DIRECTIVE CONFIGURATION
* ******************************************************************************************* */
@Directive({ property1: value1, ... })
// 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.
// List of dependency injection providers for this directive and its children.
providers: [MyService, { provide: ... }]
/* *******************************************************************************************
* COMPONENT CONFIGURATION
* https://angular.io/api/core/Component
* ******************************************************************************************* */
@Component extends @Directive, so the @Directive configuration applies to components as well
// If set, the templateUrl and styleUrl are resolved relative to the component.
moduleId: module.id
// 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'
// List of inline CSS styles or external stylesheet URLs for styling the components view.
styles: ['.primary {color: red}']
styleUrls: ['my-component.css']
/* *******************************************************************************************
* CLASS FIELD DECORATORS FOR DIRECTIVES AND COMPONENTS
* ******************************************************************************************* */
import { Input, ... } from '@angular/core';
// Declares an input property that you can update via property binding
// (example: <my-cmp [myProperty]="someExpression">).
@Input() myProperty;
// 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();
// Binds a host element property (here, the CSS class valid) to a directive/component property
// (isValid).
@HostBinding('class.valid') isValid;
// Subscribes to a host element event (click) with a directive/component method (onClick),
// optionally passing an argument ($event).
@HostListener('click', ['$event']) onClick(e) {...}
// Binds the first result of the component content query (myPredicate) to a property
// (myChildComponent) of the class.
@ContentChild(myPredicate) myChildComponent;
// Binds the results of the component content query (myPredicate) to a property
// (myChildComponents) of the class.
@ContentChildren(myPredicate) myChildComponents;
// Binds the first result of the component view query (myPredicate) to a property
// (myChildComponent) of the class. Not available for directives.
@ViewChild(myPredicate) myChildComponent;
// 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
* ******************************************************************************************* */
// (implemented as class methods)
// Called before any other lifecycle hook. Use it to inject dependencies, but avoid any serious
// work here.
constructor(myService: MyService, ...) { ... }
// Called after every change to input properties and before processing content or child views.
ngOnChanges(changeRecord) { ... }
// Called after the constructor, initializing input properties, and the first call to ngOnChanges.
ngOnInit() { ... }
// 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() { ... }
// Called after ngOnInit when the component's or directive's content has been initialized.
ngAfterContentInit() { ... }
// Called after every check of the component's or directive's content.
ngAfterContentChecked() { ... }
// Called after ngAfterContentInit when the component's views and child views / the view that a
// directive is in has been initialized.
ngAfterViewInit() { ... }
// Called after every check of the component's views and child views / the view that a directive
// is in.
ngAfterViewChecked() { ... }
// Called once, before the instance is destroyed.
ngOnDestroy() { ... }
/* *******************************************************************************************
* DEPENDENCY INJECTION CONFIGURATION
* https://angular.io/guide/dependency-injection
* ******************************************************************************************* */
// Sets or overrides the provider for MyService to the MyMockService class.
{ provide: MyService, useClass: MyMockService }
// Sets or overrides the provider for MyService to the myFactory factory function.
{ provide: MyService, useFactory: myFactory }
// Sets or overrides the provider for MyValue to the value 41.
{ provide: MyValue, useValue: 41 }
/* *******************************************************************************************
* ROUTING AND NAVIGATION
* https://angular.io/guide/router
* ******************************************************************************************* */
import { Routes, RouterModule, ... } from '@angular/router';
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' } }
]);
// 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>
// 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">
// 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(
route: ActivatedRouteSnapshot,
state: RouterStateSnapshot
): Observable<boolean>|Promise<boolean>|boolean { ... }
}
// 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(
component: T,
route: ActivatedRouteSnapshot,
state: RouterStateSnapshot
): Observable<boolean>|Promise<boolean>|boolean { ... }
}
// 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(
route: ActivatedRouteSnapshot,
state: RouterStateSnapshot
): Observable<boolean>|Promise<boolean>|boolean { ... }
}
// 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(
route: ActivatedRouteSnapshot,
state: RouterStateSnapshot
): Observable<any>|Promise<any>|any { ... }
}
// 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(
route: Route
): Observable<boolean>|Promise<boolean>|boolean { ... }
}
// 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: ...
}