Interface that a class can implement to be a guard deciding if a route can be activated. If all guards return true, navigation will continue. If any guard returns false, navigation will be cancelled. If any guard returns a UrlTree, current navigation will be cancelled and a new navigation will be kicked off to the UrlTree returned from the guard.
canActivate guard decides if route can be navigated to, which results in the creation of the route's component.
To implement the guard, create a new class and implement the
The interface can return a boolean (as a boolean, a promise, or an Observable) or the guard can navigate to another route.
If it returns a truthy value, the component will be created, otherwise it will not and the navigation gets canceled.
To guard a route, add the guard to the
canActivate property while declaring the routes in the application.
Interface that a class can implement to be a guard deciding if a child route can be activated. If all guards return true, navigation will continue. If any guard returns false, navigation will be cancelled. If any guard returns a UrlTree, current navigation will be cancelled and a new navigation will be kicked off to the UrlTree returned from the guard.
canActivateChild guard, serves the same purpose as the
canActivate guard and can prevent a route navigation.
The API to create the guard is the same, but for the
canActivateChild guard you have to implement the
To add the guard to the routes, use the
Doing this will guard all the children's routes.
The differences link
canActivatewill only execute when the parent component is not yet created. For example, if we navigate to the parent route it will be called, if we then navigate to a child route it will not. If we directly navigate to the child route, the
canActivateguard will also be executed.
canActivateChildwill always be executed while navigating to/between child routes. For example, if we're at a child route
child/1and we navigate to
child/2, the guard will get executed. If we directly navigate to a child route, the guard will also get called. If we navigate to the parent route, the
canActivateChildguard will not be fired.
canActivateis guarding the parent route, the child parameters (and data) are not available on the
canActivateguard. To be able to access the child parameters, we have to drill down the child components on the
Nice to knows link
- because the parent component gets created first, the
canActivateguard will always be called first.
- if we directly navigate to a child component and the child guard returns a falsy value then the parent component will also not be created, because the navigation is cancelled when one of the guards return a falsy value.
- when the
canActivateguard returns a falsy value, then the
canActivateChildguard will not be called.
canActivateChildguard can be rewritten as a
canActivateguard on every child route.
Example application link
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