p.location-badge.
  exported from <a href='../metadata'>angular2/metadata</a>
  defined in <a href="https://github.com/angular/angular/tree/2.0.0-alpha.36/modules/angular2/src/core/metadata/directives.ts#L728-L848">angular2/src/core/metadata/directives.ts (line 728)</a>

:markdown
  Annotations provide the additional information that Angular requires in order to run your
  application. This module
  contains <a href='ComponentMetadata-class.html'><code>ComponentMetadata</code></a>, <a href='DirectiveMetadata-class.html'><code>DirectiveMetadata</code></a>, and <a href='ViewMetadata-class.html'><code>ViewMetadata</code></a>
  annotations, as well as
  the <a href='../di/Host-var.html'><code>Host</code></a> annotation that is used by Angular to resolve dependencies.

.l-main-section
  h2 Annotations
  .l-sub-section
    h3.annotation CONST
    pre.prettyprint
      code.
        @CONST()


.l-main-section
  h2 Members
  .l-sub-section
    h3 constructor

    
    pre.prettyprint
      code.
        constructor({selector, properties, events, host, exportAs, lifecycle, bindings, viewBindings,
                       changeDetection = ChangeDetectionStrategy.Default, compileChildren = true}?: {
            selector?: string,
            properties?: string[],
            events?: string[],
            host?: StringMap&lt;string, string&gt;,
            lifecycle?: LifecycleEvent[],
            bindings?: any[],
            exportAs?: string,
            compileChildren?: boolean,
            viewBindings?: any[],
            changeDetection?: ChangeDetectionStrategy,
          })
    
    :markdown
      
      




  .l-sub-section
    h3 changeDetection

    
    :markdown
      Defines the used change detection strategy.
      
      When a component is instantiated, Angular creates a change detector, which is responsible for
      propagating the component's bindings.
      
      The `changeDetection` property defines, whether the change detection will be checked every time
      or only when the component tells it to do so.
      
      





  .l-sub-section
    h3 viewBindings

    
    :markdown
      Defines the set of injectable objects that are visible to its view dom children.
      
      ## Simple Example
      
      Here is an example of a class that can be injected:
      
      ```
      class Greeter {
         greet(name:string) {
           return 'Hello ' + name + '!';
         }
      }
      
      @Directive({
        selector: 'needs-greeter'
      })
      class NeedsGreeter {
        greeter:Greeter;
      
        constructor(greeter:Greeter) {
          this.greeter = greeter;
        }
      }
      
      @Component({
        selector: 'greet',
        viewBindings: [
          Greeter
        ]
      })
      @View({
        template: `<needs-greeter></needs-greeter>`,
        directives: [NeedsGreeter]
      })
      class HelloWorld {
      }
      
      ```