angular-cn/public/docs/js/latest/api/router/CanActivate-var.jade

.l-main-section
  h2 CanActivate <span class="type">variable</span>
  p.location-badge.
    exported from <a href='../router'>angular2/router</a>
    defined in <a href="https://github.com/angular/angular/tree/2.0.0-alpha.34/modules/angular2/src/router/lifecycle_annotations.ts#L41-L43">angular2/src/router/lifecycle_annotations.ts (line 41)</a>

  :markdown
    Defines route lifecycle method [canActivate], which is called by the router to determine
    if a component can be instantiated as part of a navigation.
    
    Note that unlike other lifecycle hooks, this one uses an annotation rather than an interface.
    This is because [canActivate] is called before the component is instantiated.
    
    If `canActivate` returns or resolves to `false`, the navigation is cancelled.
    
    If `canActivate` throws or rejects, the navigation is also cancelled.
    
    ## Example
    ```
    @Directive({
      selector: 'control-panel-cmp'
    })
    @CanActivate(() => checkIfUserIsLoggedIn())
    class ControlPanelCmp {
      // ...
    }
     ```