What are route resolvers in Angular CLI?

What are route resolvers in Angular CLI?

Route resolvers in Angular CLI are services that pre-fetch data before a route is activated.

How do I implement a route resolver in my Angular application?

To implement a route resolver, create a service that implements the Resolve interface and use it in your route configuration.

Can you show me a code example of a route resolver?

Sure! Here's a simple example:

import { Injectable } from '@angular/core';
import { Resolve, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { Observable } from 'rxjs';
import { DataService } from './data.service';

@Injectable({ providedIn: 'root' })
export class DataResolver implements Resolve<DataType> {
  constructor(private dataService: DataService) {}

  resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<DataType> {
    return this.dataService.getData();
  }
}

What happens if the resolver fails to fetch data?

If the resolver fails, the route will not activate, and you can handle the error by redirecting or showing an error page.