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Resolvers

A class that implements the Resolve interface (or a function with the same signature as the resolve() method) that you use to produce or retrieve data that is needed before navigation to a requested route can be completed.
Resolvers run after all route guards for a route tree have been executed and have succeeded. See an example of using a resolve guard to retrieve dynamic data.

Resolve

Interface that classes can implement to be a data provider. A data provider class can be used with the router to resolve data during navigation. The interface defines a resolve() method that is invoked when the navigation starts. The router waits for the data to be resolved before the route is finally activated.

Description

The following example implements a resolve() the method that retrieves the data needed to activate the requested route.
content_copy@Injectable({ providedIn: 'root' })
export class HeroResolver implements Resolve<Hero> {
constructor(private service: HeroService) {}
resolve(
route: ActivatedRouteSnapshot,
state: RouterStateSnapshot
): Observable<any>|Promise<any>|any {
return this.service.getHero(route.paramMap.get('id'));
}
}
Here, the defined resolve() function is provided as part of the Route object in the router configuration:
content_copy@NgModule({
imports: [
RouterModule.forRoot([
{
path: 'detail/:id',
component: HeroDetailComponent,
resolve: {
hero: HeroResolver
}
}
])
],
exports: [RouterModule]
})
export class AppRoutingModule {}
You can alternatively provide an in-line function with the resolve() signature:
content_copyexport const myHero: Hero = {
// ...
}
@NgModule({
imports: [
RouterModule.forRoot([
{
path: 'detail/:id',
component: HeroComponent,
resolve: {
hero: 'heroResolver'
}
}
])
],
providers: [
{
provide: 'heroResolver',
useValue: (route: ActivatedRouteSnapshot, state: RouterStateSnapshot) => myHero
}
]
})
export class AppModule {}