docs: annotations
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Misko Hevery
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@ -7,51 +7,73 @@ import {Injectable} from 'angular2/di';
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/**
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* Directives allow you to attach behavior to elements in the DOM.
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*
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* Directive is an abstract concept, instead use concrete directives such as: [Component], [Decorator] or [Viewport].
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* Directive is an abstract concept, instead use concrete directives: [Component], [DynamicComponent], [Decorator]
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* or [Viewport].
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*
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* A directive consists of a single directive annotation and a controller class. When the directive's [selector] matches
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* elements in the DOM, the following steps occur:
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*
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* 1. For each directive, the [elementInjector] resolves the directive's constructor arguments.
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* 1. For each directive, the [ElementInjector] attempts to resolve the directive's constructor arguments.
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* 2. Angular instantiates directives for each matched element using [ElementInjector].
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*
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* Angular guarantees the following constraints:
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* - Directives are instantiated in a depth-first order, according to the order in which they appear in the [View].
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* - Injection cannot cross a Shadow DOM boundary. Angular looks for directives in the current template only.
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* ## Understanding How Injection Works
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*
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* The constructor arguments for a directive may be:
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* - other directives, as annotated by:
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* - `@Ancestor() d:Type`: any directive that matches the type between the current element (excluded) and the Shadow DOM root.
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* - `@Parent() d:Type`: any directive that matches the type on a direct parent element only.
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* - `d:Type`: a directive on the current element only.
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* - `@Children query:Query<Type>`: A live collection of direct child directives.
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* - `@Descendants query:Query<Type>`: A live collection of any child directives.
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* - element specific special objects:
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* - [NgElement] (DEPRECATED: replacment coming)
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* - [ViewContainer] (Only for [Viewport])
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* - [BindingPropagation] Used for controlling change detection
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* - Component level injectables as declared by [Component.services] of a parent compontent.
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* There are three stages of injection resolution.
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* - *Pre-existing Injectors*:
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* - The terminal [Injector] cannot resolve dependencies. It either throws an error or, if the dependency was
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* specified as `@Optional`, returns `null`.
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* - The primordial injector resolves browser singleton resources, such as: cookies, title, location, and others.
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* - *Component Injectors*: Each `@Component` has its own [Injector], and they follow the same parent-child hierachy
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* as the components in the DOM.
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* - *Element Injectors*: Each component has a Shadow DOM. Within the Shadow DOM each element has an [ElementInjector]
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* which follow the same parent-child hiercachy as the DOM elements themselves.
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*
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* When resolving dependencies, the current injector is asked to resolve the dependency first, and if it does not
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* have it, it delegates to the parent injector.
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*
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* Angular then resolves dependencies as follows, according to the order in which they appear in the [View]:
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*
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* 1. Dependencies on element injectors and their parents until it encounters a Shadow DOM boundary
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* 2. Dependencies on component injectors and their parents until it encounters the root component
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* 3. Dependencies on pre-existing injectors
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*
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*
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* The [ElementInjector] can inject other directives, element-specific special objects, or can delegate to the parent
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* injector.
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*
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* To inject other directives, declare the constructor parameter as:
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* - `directive:DirectiveType`: a directive on the current element only
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* - `@Ancestor() d:Type`: any directive that matches the type between the current element (excluded) and the Shadow DOM root [TODO: what does (excluded) mean? Does this apply to the @Parent annotation also?]
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* - `@Parent() d:Type`: any directive that matches the type on a direct parent element only
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* - `@Children query:Query<Type>`: A live collection of direct child directives
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* - `@Descendants query:Query<Type>`: A live collection of any child directives
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*
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* To inject element-specific special objects, declare the constructor parameter as:
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* - `element: NgElement` to obtain a DOM element (DEPRECATED: replacment coming)
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* - `viewContainer: ViewContainer` to control child template instantiation, for [Viewport] directives only
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* - `bindingPropagation: BindingPropagation` to control change detection in a more granular way
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*
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* ## Example
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*
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* Assuming this HTML structure:
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* The following example demonstrates how dependency injection resolves constructor arguments in practice.
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*
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*
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* Assume this HTML structure:
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*
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* ```
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* <div marker="1">
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* <div marker="2">
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* <div marker="3" example>
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* <div marker="4">
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* <div marker="5"></div>
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* <div dependency="1">
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* <div dependency="2">
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* <div dependency="3" my-directive>
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* <div dependency="4">
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* <div dependency="5"></div>
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* </div>
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* <div marker="6"></div>
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* <div dependency="6"></div>
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* </div>
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* </div>
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* </div>
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* ```
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*
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* With the following `Marker` decorator and `SomeService` class:
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* With the following `dependency` decorator and `SomeService` injectable class.
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*
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* ```
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* @Injectable()
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@ -59,98 +81,102 @@ import {Injectable} from 'angular2/di';
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* }
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*
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* @Decorator({
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* selector: '[marker]',
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* selector: '[dependency]',
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* bind: {
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* 'id':'marker'
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* 'id':'dependency'
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* }
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* })
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* class Marker {
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* class Dependency {
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* id:string;
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* }
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* ```
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*
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* We would like to demonstrate how we can inject different instances into a directive. In each case injecting
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* is as simple as asking for the type in the constructor.
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*
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* Let's step through the different ways in which `MyDirective` could be declared...
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*
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* ### No injection
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*
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* A directive can have a constructor with no arguments in which case nothing is injected into it.
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* Here the constructor is declared with no arguments, so nothing is injected into `MyDirective`.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor() {
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* }
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* }
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* ```
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*
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* This directive would return nothing for the example code above. [TODO: True? We spent a lot of time talking about
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* errors but in this case, there's nothing to error on, right? I don't understand the diff between "returns" and "injects"
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* when the example is showing a directive not the template. Which is the correct verb?]
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*
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* ### Injecting from application injector
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* ### Component-level injection
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*
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* Directives can inject any injectable instance from the closest component injector or any of its parents.
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* To inject from component injector the directive list the dependency as such:
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*
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* Here, the constructor declares a parameter, `someService`, and injects the `SomeService` type from the parent
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* component's injector.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* constructor(someService:SomeService) {
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(someService: SomeService) {
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* }
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* }
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* ```
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*
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* This directive would return `dependency=3` for the example code above. [TODO: True? Is "return" the right verb?]
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*
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* ### Injecting directive from current element
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* ### Injecting a directive from the current element
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*
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* Directives can inject other directives declared on the current element. If no such type is found the injection will
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* delegate to component injector which will throw an error (or optionally return null as described below).
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* Directives can inject other directives declared on the current element.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* constructor(marker:Marker) {
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* expect(marker.id).toEqual(2);
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(dependency: Dependency) {
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* expect(dependency.id).toEqual(2);
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* }
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* }
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* ```
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* This directive would also return `dependency=3` for the example code above. [TODO: True? Why is this the same?]
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*
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*
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* ### Injecting a directive from a direct parent element
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*
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* Directives can inject other directives declared on a direct parent element. By definition, a directive with a
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* `@Parent` annotation does not attempt to resolve dependencies for the current element, even if this would satisfy
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* the dependency. [TODO: did I get the subject/verb right?]
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*
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* ```
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(@Parent() dependency: Dependency) {
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* expect(dependency.id).toEqual(2);
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* }
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* }
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* ```
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* This directive would return `dependency=2` for the example code above. [TODO: True?]
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*
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* ### Injecting a directive from any ancestor elements
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*
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* Directives can inject other directives declared on any ancestor element, i.e. on the parent element and its parents.
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* By definition, a directive with an `@Ancestor` annotation does not attempt to resolve dependencies for the current
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* element, even if this would satisfy the dependency. [TODO: did I get the subject/verb right? ]
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*
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* Unlike the `@Parent` which only checks the parent `@Ancestor` checks the parent, as well as its
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* parents recursivly. If `dependency="2"` would not be present this injection would return `dependency="1"`.
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* ```
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(@Ancestor() dependency: Dependency) {
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* expect(dependency.id).toEqual(2);
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* }
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* }
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* ```
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*
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*
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* ### Injecting directive from parent element
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*
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* Directives can inject other directives declared on parent element. If no such type is found the injection will
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* delegate to component injector which will throw.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* constructor(@Parent() marker:Marker) {
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* expect(marker.id).toEqual(2);
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* }
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* }
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* ```
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*
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* The `@Parent` annotation will explicitly skip the current element, even if the current element could satisfy
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* the dependency.
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*
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*
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* ### Injecting directive from ancestor element.
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*
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* Directives can inject other directives declared on ancestor (parent plus its parents) elements. If no such type is
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* found the injection will delegate to component injector which will throw.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* constructor(@Ancestor() marker:Marker) {
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* expect(marker.id).toEqual(2);
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* }
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* }
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* ```
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*
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* The `@Ancestor` annotation will explicitly skip the current element, even if the current element could satisfy
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* the dependency. Unlike the `@Parent` which only checks the parent `@Ancestor` checks the parent, as well as its
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* parents recursivly. If `marker="2"` would not be preset this injection would return `marker="1"`.
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*
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* This directive would also return `dependency=2` for the example code above. If `dependency=2` hadn't been declared
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* on the parent `div`, this directive would return `d[TODO: True?]
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*
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* ### Injecting query of child directives. [PENDING IMPLEMENTATION]
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*
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@ -159,10 +185,10 @@ import {Injectable} from 'angular2/di';
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* which can than be filled once the data is needed.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* constructor(@Children() markers:Query<Maker>) {
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* // markers will eventuall contain: [4, 6]
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(@Children() dependencys:Query<Maker>) {
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* // dependencys will eventuall contain: [4, 6]
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* // this will upbate if children are added/removed/moved,
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* // for example by having for or if.
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* }
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@ -175,10 +201,10 @@ import {Injectable} from 'angular2/di';
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* Similar to `@Children` but also includ childre of those children.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* constructor(@Children() markers:Query<Maker>) {
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* // markers will eventuall contain: [4, 5, 6]
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(@Children() dependencys:Query<Maker>) {
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* // dependencys will eventuall contain: [4, 5, 6]
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* // this will upbate if children are added/removed/moved,
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* // for example by having for or if.
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* }
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@ -192,8 +218,8 @@ import {Injectable} from 'angular2/di';
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* use case angular supports `@Optional` injection.
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*
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* ```
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* @Decorator({ selector: '[example]' })
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* class Example {
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* @Decorator({ selector: '[my-directive]' })
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* class MyDirective {
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* constructor(@Optional() @Ancestor() form:Form) {
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* // this will search for a Form directive above itself,
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* // and inject null if not found
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@ -522,6 +548,72 @@ export class Component extends Directive {
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}
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}
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/**
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* DynamicComponents allow loading child components impretivly.
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*
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* A Component can be made of other compontents. This recursive nature must be resolved synchronously during the
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* component template processing. This means that all templates are resolved synchronously. This prevents lazy loading
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* of code or delayed binding of views to the components.
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*
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* A DynamicComponent is a placeholder into which a regular component can be loaded imperativly and thus breaking
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* the all components must be resolved synchronously restriction. Once loaded the component is premanent.
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*
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*
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* ## Example
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* @DynamicComponent({
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* selector: 'dynamic-comp'
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* })
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* class DynamicComp {
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* done;
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* constructor(loader:PrivateComponentLoader, location:PrivateComponentLocation) {
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* this.done = loader.load(HelloCmp, location);
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* }
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* }
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*
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* @Component({
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* selector: 'hello-cmp'
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* })
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* @Template({
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* inline: "{{greeting}}"
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* })
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* class HelloCmp {
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* greeting:string;
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* constructor() {
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* this.greeting = "hello";
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* }
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* }
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*
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*
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* @publicModule angular2/annotations
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*/
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export class DynamicComponent extends Directive {
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services:any; //List;
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@CONST()
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constructor({
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selector,
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bind,
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events,
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services,
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lifecycle
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}:{
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selector:string,
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bind:Object,
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events:Object,
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services:List,
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lifecycle:List
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}={}) {
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super({
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selector: selector,
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bind: bind,
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events: events,
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lifecycle: lifecycle
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});
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this.services = services;
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}
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}
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/**
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* Decorators allow attaching behavior to DOM elements in a composable manner.
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*
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@ -577,37 +669,6 @@ export class Component extends Directive {
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* ```
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* @publicModule angular2/annotations
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*/
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export class DynamicComponent extends Directive {
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services:any; //List;
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@CONST()
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constructor({
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selector,
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bind,
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events,
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services,
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lifecycle
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}:{
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selector:string,
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bind:Object,
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events:Object,
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services:List,
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lifecycle:List
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}={}) {
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super({
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selector: selector,
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bind: bind,
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events: events,
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lifecycle: lifecycle
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});
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this.services = services;
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}
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}
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/**
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* @publicModule angular2/angular2
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*/
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export class Decorator extends Directive {
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compileChildren: boolean;
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@CONST()
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@ -4,7 +4,8 @@ import {DependencyAnnotation} from 'angular2/di';
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/**
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* The directive can only be injected from the current element
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* or from its parent.
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* @publicModule angular2/angular2
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*
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* @publicModule angular2/annotations
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*/
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export class Parent extends DependencyAnnotation {
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@CONST()
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@ -16,7 +17,8 @@ export class Parent extends DependencyAnnotation {
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/**
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* The directive can only be injected from the current element
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* or from its ancestor.
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* @publicModule angular2/angular2
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*
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* @publicModule angular2/annotations
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*/
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export class Ancestor extends DependencyAnnotation {
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@CONST()
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