chore(docs): copy [Decorator]Metadata docs to the [Decorator]

This allows editors to show the docs when users navigate to definition.

See #4668

Closes #4683
This commit is contained in:
Alex Eagle 2015-10-12 10:12:11 -07:00 committed by Alex Eagle
parent 1aeafd31bd
commit 947bf11cb6
1 changed files with 850 additions and 17 deletions

View File

@ -505,82 +505,915 @@ export interface HostListenerFactory {
new (eventName: string, args?: string[]): any;
}
// TODO(alexeagle): remove the duplication of this doc. It is copied from ComponentMetadata.
/**
* {@link ComponentMetadata} factory function.
* Declare reusable UI building blocks for an application.
*
* Each Angular component requires a single `@Component` and at least one `@View` annotation. The
* `@Component`
* annotation specifies when a component is instantiated, and which properties and hostListeners it
* binds to.
*
* When a component is instantiated, Angular
* - creates a shadow DOM for the component.
* - loads the selected template into the shadow DOM.
* - creates all the injectable objects configured with `providers` and `viewProviders`.
*
* All template expressions and statements are then evaluated against the component instance.
*
* For details on the `@View` annotation, see {@link ViewMetadata}.
*
* ## Lifecycle hooks
*
* When the component class implements some {@link angular2/lifecycle_hooks} the callbacks are
* called by the change detection at defined points in time during the life of the component.
*
* ## Example
*
* ```
* @Component({
* selector: 'greet',
* template: 'Hello {{name}}!'
* })
* class Greet {
* name: string;
*
* constructor() {
* this.name = 'World';
* }
* }
* ```
*
*/
export var Component: ComponentFactory =
<ComponentFactory>makeDecorator(ComponentMetadata, (fn: any) => fn.View = View);
// TODO(alexeagle): remove the duplication of this doc. It is copied from DirectiveMetadata.
/**
* {@link DirectiveMetadata} factory function.
* Directives allow you to attach behavior to elements in the DOM.
*
* {@link DirectiveMetadata}s with an embedded view are called {@link ComponentMetadata}s.
*
* A directive consists of a single directive annotation and a controller class. When the
* directive's `selector` matches
* elements in the DOM, the following steps occur:
*
* 1. For each directive, the `ElementInjector` attempts to resolve the directive's constructor
* arguments.
* 2. Angular instantiates directives for each matched element using `ElementInjector` in a
* depth-first order,
* as declared in the HTML.
*
* ## Understanding How Injection Works
*
* There are three stages of injection resolution.
* - *Pre-existing Injectors*:
* - The terminal {@link Injector} cannot resolve dependencies. It either throws an error or, if
* the dependency was
* specified as `@Optional`, returns `null`.
* - The platform injector resolves browser singleton resources, such as: cookies, title,
* location, and others.
* - *Component Injectors*: Each component instance has its own {@link Injector}, and they follow
* the same parent-child hierarchy
* as the component instances in the DOM.
* - *Element Injectors*: Each component instance has a Shadow DOM. Within the Shadow DOM each
* element has an `ElementInjector`
* which follow the same parent-child hierarchy as the DOM elements themselves.
*
* When a template is instantiated, it also must instantiate the corresponding directives in a
* depth-first order. The
* current `ElementInjector` resolves the constructor dependencies for each directive.
*
* Angular then resolves dependencies as follows, according to the order in which they appear in the
* {@link ViewMetadata}:
*
* 1. Dependencies on the current element
* 2. Dependencies on element injectors and their parents until it encounters a Shadow DOM boundary
* 3. Dependencies on component injectors and their parents until it encounters the root component
* 4. Dependencies on pre-existing injectors
*
*
* The `ElementInjector` can inject other directives, element-specific special objects, or it can
* delegate to the parent
* injector.
*
* To inject other directives, declare the constructor parameter as:
* - `directive:DirectiveType`: a directive on the current element only
* - `@Host() directive:DirectiveType`: any directive that matches the type between the current
* element and the
* Shadow DOM root.
* - `@Query(DirectiveType) query:QueryList<DirectiveType>`: A live collection of direct child
* directives.
* - `@QueryDescendants(DirectiveType) query:QueryList<DirectiveType>`: A live collection of any
* child directives.
*
* To inject element-specific special objects, declare the constructor parameter as:
* - `element: ElementRef` to obtain a reference to logical element in the view.
* - `viewContainer: ViewContainerRef` to control child template instantiation, for
* {@link DirectiveMetadata} directives only
* - `bindingPropagation: BindingPropagation` to control change detection in a more granular way.
*
* ## Example
*
* The following example demonstrates how dependency injection resolves constructor arguments in
* practice.
*
*
* Assume this HTML template:
*
* ```
* <div dependency="1">
* <div dependency="2">
* <div dependency="3" my-directive>
* <div dependency="4">
* <div dependency="5"></div>
* </div>
* <div dependency="6"></div>
* </div>
* </div>
* </div>
* ```
*
* With the following `dependency` decorator and `SomeService` injectable class.
*
* ```
* @Injectable()
* class SomeService {
* }
*
* @Directive({
* selector: '[dependency]',
* inputs: [
* 'id: dependency'
* ]
* })
* class Dependency {
* id:string;
* }
* ```
*
* Let's step through the different ways in which `MyDirective` could be declared...
*
*
* ### No injection
*
* Here the constructor is declared with no arguments, therefore nothing is injected into
* `MyDirective`.
*
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor() {
* }
* }
* ```
*
* This directive would be instantiated with no dependencies.
*
*
* ### Component-level injection
*
* Directives can inject any injectable instance from the closest component injector or any of its
* parents.
*
* Here, the constructor declares a parameter, `someService`, and injects the `SomeService` type
* from the parent
* component's injector.
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor(someService: SomeService) {
* }
* }
* ```
*
* This directive would be instantiated with a dependency on `SomeService`.
*
*
* ### Injecting a directive from the current element
*
* Directives can inject other directives declared on the current element.
*
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor(dependency: Dependency) {
* expect(dependency.id).toEqual(3);
* }
* }
* ```
* This directive would be instantiated with `Dependency` declared at the same element, in this case
* `dependency="3"`.
*
* ### Injecting a directive from any ancestor elements
*
* Directives can inject other directives declared on any ancestor element (in the current Shadow
* DOM), i.e. on the current element, the
* parent element, or its parents.
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor(@Host() dependency: Dependency) {
* expect(dependency.id).toEqual(2);
* }
* }
* ```
*
* `@Host` checks the current element, the parent, as well as its parents recursively. If
* `dependency="2"` didn't
* exist on the direct parent, this injection would
* have returned
* `dependency="1"`.
*
*
* ### Injecting a live collection of direct child directives
*
*
* A directive can also query for other child directives. Since parent directives are instantiated
* before child directives, a directive can't simply inject the list of child directives. Instead,
* the directive injects a {@link QueryList}, which updates its contents as children are added,
* removed, or moved by a directive that uses a {@link ViewContainerRef} such as a `ng-for`, an
* `ng-if`, or an `ng-switch`.
*
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor(@Query(Dependency) dependencies:QueryList<Dependency>) {
* }
* }
* ```
*
* This directive would be instantiated with a {@link QueryList} which contains `Dependency` 4 and
* 6. Here, `Dependency` 5 would not be included, because it is not a direct child.
*
* ### Injecting a live collection of descendant directives
*
* By passing the descendant flag to `@Query` above, we can include the children of the child
* elements.
*
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor(@Query(Dependency, {descendants: true}) dependencies:QueryList<Dependency>) {
* }
* }
* ```
*
* This directive would be instantiated with a Query which would contain `Dependency` 4, 5 and 6.
*
* ### Optional injection
*
* The normal behavior of directives is to return an error when a specified dependency cannot be
* resolved. If you
* would like to inject `null` on unresolved dependency instead, you can annotate that dependency
* with `@Optional()`.
* This explicitly permits the author of a template to treat some of the surrounding directives as
* optional.
*
* ```
* @Directive({ selector: '[my-directive]' })
* class MyDirective {
* constructor(@Optional() dependency:Dependency) {
* }
* }
* ```
*
* This directive would be instantiated with a `Dependency` directive found on the current element.
* If none can be
* found, the injector supplies `null` instead of throwing an error.
*
* ## Example
*
* Here we use a decorator directive to simply define basic tool-tip behavior.
*
* ```
* @Directive({
* selector: '[tooltip]',
* inputs: [
* 'text: tooltip'
* ],
* host: {
* '(mouseenter)': 'onMouseEnter()',
* '(mouseleave)': 'onMouseLeave()'
* }
* })
* class Tooltip{
* text:string;
* overlay:Overlay; // NOT YET IMPLEMENTED
* overlayManager:OverlayManager; // NOT YET IMPLEMENTED
*
* constructor(overlayManager:OverlayManager) {
* this.overlay = overlay;
* }
*
* onMouseEnter() {
* // exact signature to be determined
* this.overlay = this.overlayManager.open(text, ...);
* }
*
* onMouseLeave() {
* this.overlay.close();
* this.overlay = null;
* }
* }
* ```
* In our HTML template, we can then add this behavior to a `<div>` or any other element with the
* `tooltip` selector,
* like so:
*
* ```
* <div tooltip="some text here"></div>
* ```
*
* Directives can also control the instantiation, destruction, and positioning of inline template
* elements:
*
* A directive uses a {@link ViewContainerRef} to instantiate, insert, move, and destroy views at
* runtime.
* The {@link ViewContainerRef} is created as a result of `<template>` element, and represents a
* location in the current view
* where these actions are performed.
*
* Views are always created as children of the current {@link ViewMetadata}, and as siblings of the
* `<template>` element. Thus a
* directive in a child view cannot inject the directive that created it.
*
* Since directives that create views via ViewContainers are common in Angular, and using the full
* `<template>` element syntax is wordy, Angular
* also supports a shorthand notation: `<li *foo="bar">` and `<li template="foo: bar">` are
* equivalent.
*
* Thus,
*
* ```
* <ul>
* <li *foo="bar" title="text"></li>
* </ul>
* ```
*
* Expands in use to:
*
* ```
* <ul>
* <template [foo]="bar">
* <li title="text"></li>
* </template>
* </ul>
* ```
*
* Notice that although the shorthand places `*foo="bar"` within the `<li>` element, the binding for
* the directive
* controller is correctly instantiated on the `<template>` element rather than the `<li>` element.
*
* ## Lifecycle hooks
*
* When the directive class implements some {@link angular2/lifecycle_hooks} the callbacks are
* called by the change detection at defined points in time during the life of the directive.
*
* ## Example
*
* Let's suppose we want to implement the `unless` behavior, to conditionally include a template.
*
* Here is a simple directive that triggers on an `unless` selector:
*
* ```
* @Directive({
* selector: '[unless]',
* inputs: ['unless']
* })
* export class Unless {
* viewContainer: ViewContainerRef;
* templateRef: TemplateRef;
* prevCondition: boolean;
*
* constructor(viewContainer: ViewContainerRef, templateRef: TemplateRef) {
* this.viewContainer = viewContainer;
* this.templateRef = templateRef;
* this.prevCondition = null;
* }
*
* set unless(newCondition) {
* if (newCondition && (isBlank(this.prevCondition) || !this.prevCondition)) {
* this.prevCondition = true;
* this.viewContainer.clear();
* } else if (!newCondition && (isBlank(this.prevCondition) || this.prevCondition)) {
* this.prevCondition = false;
* this.viewContainer.create(this.templateRef);
* }
* }
* }
* ```
*
* We can then use this `unless` selector in a template:
* ```
* <ul>
* <li *unless="expr"></li>
* </ul>
* ```
*
* Once the directive instantiates the child view, the shorthand notation for the template expands
* and the result is:
*
* ```
* <ul>
* <template [unless]="exp">
* <li></li>
* </template>
* <li></li>
* </ul>
* ```
*
* Note also that although the `<li></li>` template still exists inside the `<template></template>`,
* the instantiated
* view occurs on the second `<li></li>` which is a sibling to the `<template>` element.
*/
export var Directive: DirectiveFactory = <DirectiveFactory>makeDecorator(DirectiveMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from ViewMetadata.
/**
* {@link ViewMetadata} factory function.
* Metadata properties available for configuring Views.
*
* Each Angular component requires a single `@Component` and at least one `@View` annotation. The
* `@View` annotation specifies the HTML template to use, and lists the directives that are active
* within the template.
*
* When a component is instantiated, the template is loaded into the component's shadow root, and
* the expressions and statements in the template are evaluated against the component.
*
* For details on the `@Component` annotation, see {@link ComponentMetadata}.
*
* ## Example
*
* ```
* @Component({
* selector: 'greet',
* template: 'Hello {{name}}!',
* directives: [GreetUser, Bold]
* })
* class Greet {
* name: string;
*
* constructor() {
* this.name = 'World';
* }
* }
* ```
*/
export var View: ViewFactory =
<ViewFactory>makeDecorator(ViewMetadata, (fn: any) => fn.View = View);
// TODO(alexeagle): remove the duplication of this doc. It is copied from AttributeMetadata.
/**
* {@link AttributeMetadata} factory function.
* Metadata properties available for configuring Views.
*
* Each Angular component requires a single `@Component` and at least one `@View` annotation. The
* `@View` annotation specifies the HTML template to use, and lists the directives that are active
* within the template.
*
* When a component is instantiated, the template is loaded into the component's shadow root, and
* the expressions and statements in the template are evaluated against the component.
*
* For details on the `@Component` annotation, see {@link ComponentMetadata}.
*
* ## Example
*
* ```
* @Component({
* selector: 'greet',
* template: 'Hello {{name}}!',
* directives: [GreetUser, Bold]
* })
* class Greet {
* name: string;
*
* constructor() {
* this.name = 'World';
* }
* }
* ```
*/
export var Attribute: AttributeFactory = makeParamDecorator(AttributeMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from QueryMetadata.
/**
* {@link QueryMetadata} factory function.
* Declares an injectable parameter to be a live list of directives or variable
* bindings from the content children of a directive.
*
* ### Example ([live demo](http://plnkr.co/edit/lY9m8HLy7z06vDoUaSN2?p=preview))
*
* Assume that `<tabs>` component would like to get a list its children `<pane>`
* components as shown in this example:
*
* ```html
* <tabs>
* <pane title="Overview">...</pane>
* <pane *ng-for="#o of objects" [title]="o.title">{{o.text}}</pane>
* </tabs>
* ```
*
* The preferred solution is to query for `Pane` directives using this decorator.
*
* ```javascript
* @Component({
* selector: 'pane',
* inputs: ['title']
* })
* class Pane {
* title:string;
* }
*
* @Component({
* selector: 'tabs',
* template: `
* <ul>
* <li *ng-for="#pane of panes">{{pane.title}}</li>
* </ul>
* <content></content>
* `
* })
* class Tabs {
* panes: QueryList<Pane>;
* constructor(@Query(Pane) panes:QueryList<Pane>) {
* this.panes = panes;
* }
* }
* ```
*
* A query can look for variable bindings by passing in a string with desired binding symbol.
*
* ### Example ([live demo](http://plnkr.co/edit/sT2j25cH1dURAyBRCKx1?p=preview))
* ```html
* <seeker>
* <div #findme>...</div>
* </seeker>
*
* @Component({ selector: 'foo' })
* class seeker {
* constructor(@Query('findme') elList: QueryList<ElementRef>) {...}
* }
* ```
*
* In this case the object that is injected depend on the type of the variable
* binding. It can be an ElementRef, a directive or a component.
*
* Passing in a comma separated list of variable bindings will query for all of them.
*
* ```html
* <seeker>
* <div #find-me>...</div>
* <div #find-me-too>...</div>
* </seeker>
*
* @Component({
* selector: 'foo'
* })
* class Seeker {
* constructor(@Query('findMe, findMeToo') elList: QueryList<ElementRef>) {...}
* }
* ```
*
* Configure whether query looks for direct children or all descendants
* of the querying element, by using the `descendants` parameter.
* It is set to `false` by default.
*
* ### Example ([live demo](http://plnkr.co/edit/wtGeB977bv7qvA5FTYl9?p=preview))
* ```html
* <container #first>
* <item>a</item>
* <item>b</item>
* <container #second>
* <item>c</item>
* </container>
* </container>
* ```
*
* When querying for items, the first container will see only `a` and `b` by default,
* but with `Query(TextDirective, {descendants: true})` it will see `c` too.
*
* The queried directives are kept in a depth-first pre-order with respect to their
* positions in the DOM.
*
* Query does not look deep into any subcomponent views.
*
* Query is updated as part of the change-detection cycle. Since change detection
* happens after construction of a directive, QueryList will always be empty when observed in the
* constructor.
*
* The injected object is an unmodifiable live list.
* See {@link QueryList} for more details.
*/
export var Query: QueryFactory = makeParamDecorator(QueryMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from ContentChildrenMetadata.
/**
* {@link ContentChildrenMetadata} factory function.
* Configures a content query.
*
* Content queries are set before the `afterContentInit` callback is called.
*
* ### Example
*
* ```
* @Directive({
* selector: 'someDir'
* })
* class SomeDir {
* @ContentChildren(ChildDirective) contentChildren: QueryList<ChildDirective>;
*
* afterContentInit() {
* // contentChildren is set
* }
* }
* ```
*/
export var ContentChildren: ContentChildrenFactory = makePropDecorator(ContentChildrenMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from ContentChildMetadata.
/**
* {@link ContentChildMetadata} factory function.
* Configures a content query.
*
* Content queries are set before the `afterContentInit` callback is called.
*
* ### Example
*
* ```
* @Directive({
* selector: 'someDir'
* })
* class SomeDir {
* @ContentChild(ChildDirective) contentChild;
*
* afterContentInit() {
* // contentChild is set
* }
* }
* ```
*/
export var ContentChild: ContentChildFactory = makePropDecorator(ContentChildMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from ViewChildrenMetadata.
/**
* {@link ViewChildrenMetadata} factory function.
* Configures a view query.
*
* View queries are set before the `afterViewInit` callback is called.
*
* ### Example
*
* ```
* @Component({
* selector: 'someDir',
* templateUrl: 'someTemplate',
* directives: [ItemDirective]
* })
* class SomeDir {
* @ViewChildren(ItemDirective) viewChildren: QueryList<ItemDirective>;
*
* afterViewInit() {
* // viewChildren is set
* }
* }
* ```
*/
export var ViewChildren: ViewChildrenFactory = makePropDecorator(ViewChildrenMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from ViewChildMetadata.
/**
* {@link ViewChildMetadata} factory function.
* Configures a view query.
*
* View queries are set before the `afterViewInit` callback is called.
*
* ### Example
*
* ```
* @Component({
* selector: 'someDir',
* templateUrl: 'someTemplate',
* directives: [ItemDirective]
* })
* class SomeDir {
* @ViewChild(ItemDirective) viewChild:ItemDirective;
*
* afterViewInit() {
* // viewChild is set
* }
* }
* ```
*/
export var ViewChild: ViewChildFactory = makePropDecorator(ViewChildMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from ViewQueryMetadata.
/**
* {@link di/ViewQueryMetadata} factory function.
* Similar to {@link QueryMetadata}, but querying the component view, instead of
* the content children.
*
* ### Example ([live demo](http://plnkr.co/edit/eNsFHDf7YjyM6IzKxM1j?p=preview))
*
* ```javascript
* @Component({...})
* @View({
* template: `
* <item> a </item>
* <item> b </item>
* <item> c </item>
* `
* })
* class MyComponent {
* shown: boolean;
*
* constructor(private @Query(Item) items:QueryList<Item>) {
* items.onChange(() => console.log(items.length));
* }
* }
* ```
*
* Supports the same querying parameters as {@link QueryMetadata}, except
* `descendants`. This always queries the whole view.
*
* As `shown` is flipped between true and false, items will contain zero of one
* items.
*
* Specifies that a {@link QueryList} should be injected.
*
* The injected object is an iterable and observable live list.
* See {@link QueryList} for more details.
*/
export var ViewQuery: QueryFactory = makeParamDecorator(ViewQueryMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from PipeMetadata.
/**
* {@link PipeMetadata} factory function.
* Declare reusable pipe function.
*
* ## Example
*
* ```
* @Pipe({
* name: 'lowercase'
* })
* class Lowercase {
* transform(v, args) { return v.toLowerCase(); }
* }
* ```
*/
export var Pipe: PipeFactory = <PipeFactory>makeDecorator(PipeMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from InputMetadata.
/**
* {@link InputMetadata} factory function.
* Declares a data-bound input property.
*
* See {@link InputMetadata}.
* Angular automatically updates data-bound properties during change detection.
*
* `InputMetadata` takes an optional parameter that specifies the name
* used when instantiating a component in the template. When not provided,
* the name of the decorated property is used.
*
* ### Example
*
* The following example creates a component with two input properties.
*
* ```typescript
* @Component({
* selector: 'bank-account',
* template: `
* Bank Name: {{bankName}}
* Account Id: {{id}}
* `
* })
* class BankAccount {
* @Input() bankName: string;
* @Input('account-id') id: string;
*
* // this property is not bound, and won't be automatically updated by Angular
* normalizedBankName: string;
* }
*
* @Component({
* selector: 'app',
* template: `
* <bank-account bank-name="RBC" account-id="4747"></bank-account>
* `,
* directives: [BankAccount]
* })
* class App {}
*
* bootstrap(App);
* ```
*/
export var Input: InputFactory = makePropDecorator(InputMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from OutputMetadata.
/**
* {@link OutputMetadata} factory function.
* Declares an event-bound output property.
*
* See {@link OutputMetadata}.
* When an output property emits an event, an event handler attached to that event
* the template is invoked.
*
* `OutputMetadata` takes an optional parameter that specifies the name
* used when instantiating a component in the template. When not provided,
* the name of the decorated property is used.
*
* ### Example
*
* ```typescript
* @Directive({
* selector: 'interval-dir',
* })
* class IntervalDir {
* @Output() everySecond = new EventEmitter();
* @Output('everyFiveSeconds') five5Secs = new EventEmitter();
*
* constructor() {
* setInterval(() => this.everySecond.next("event"), 1000);
* setInterval(() => this.five5Secs.next("event"), 5000);
* }
* }
*
* @Component({
* selector: 'app',
* template: `
* <interval-dir (every-second)="everySecond()" (every-five-seconds)="everyFiveSeconds()">
* </interval-dir>
* `,
* directives: [IntervalDir]
* })
* class App {
* everySecond() { console.log('second'); }
* everyFiveSeconds() { console.log('five seconds'); }
* }
* bootstrap(App);
* ```
*/
export var Output: OutputFactory = makePropDecorator(OutputMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from HostBindingMetadata.
/**
* {@link HostBindingMetadata} factory function.
* Declares a host property binding.
*
* Angular automatically checks host property bindings during change detection.
* If a binding changes, it will update the host element of the directive.
*
* `HostBindingMetadata` takes an optional parameter that specifies the property
* name of the host element that will be updated. When not provided,
* the class property name is used.
*
* ### Example
*
* The following example creates a directive that sets the `valid` and `invalid` classes
* on the DOM element that has ng-model directive on it.
*
* ```typescript
* @Directive({selector: '[ng-model]'})
* class NgModelStatus {
* constructor(public control:NgModel) {}
* @HostBinding('[class.valid]') get valid { return this.control.valid; }
* @HostBinding('[class.invalid]') get invalid { return this.control.invalid; }
* }
*
* @Component({
* selector: 'app',
* template: `<input [(ng-model)]="prop">`,
* directives: [FORM_DIRECTIVES, NgModelStatus]
* })
* class App {
* prop;
* }
*
* bootstrap(App);
* ```
*/
export var HostBinding: HostBindingFactory = makePropDecorator(HostBindingMetadata);
// TODO(alexeagle): remove the duplication of this doc. It is copied from HostListenerMetadata.
/**
* {@link HostListenerMetadata} factory function.
* Declares a host listener.
*
* Angular will invoke the decorated method when the host element emits the specified event.
*
* If the decorated method returns `false`, then `preventDefault` is applied on the DOM
* event.
*
* ### Example
*
* The following example declares a directive that attaches a click listener to the button and
* counts clicks.
*
* ```typescript
* @Directive({selector: 'button[counting]'})
* class CountClicks {
* numberOfClicks = 0;
*
* @HostListener('click', ['$event.target'])
* onClick(btn) {
* console.log("button", btn, "number of clicks:", this.numberOfClicks++);
* }
* }
*
* @Component({
* selector: 'app',
* template: `<button counting>Increment</button>`,
* directives: [CountClicks]
* })
* class App {}
*
* bootstrap(App);
* ```
*/
export var HostListener: HostListenerFactory = makePropDecorator(HostListenerMetadata);