Resolver In Angular

In Angular, a resolver is a type of service that helps to fetch data asynchronously before a route is activated. Resolvers are used to ensure that the data required by a component is available before the component is rendered, preventing empty or incomplete data from being displayed.

A resolver implements the Resolve interface from the @angular/router package and provides a resolve() method. The resolve() method returns an observable or a promise that resolves to the data that needs to be fetched. The Resolve interface requires the implementation of the resolve() method, which takes an ActivatedRouteSnapshot object as a parameter and returns a promise or an observable.

Here’s an example of a resolver that returns data as an observable:

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<any> {

  constructor(private dataService: DataService) { }

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

In this example, we’re creating a resolver called DataResolver that returns data as observable. The resolve() method…