Explain the difference between ActivatedRoute and RouterState in Angular

In Angular, ActivatedRoute and RouterState are related concepts that are part of the Angular Router module (@angular/router). They provide different ways to access information about the current route and its state within an Angular application.

ActivatedRoute

ActivatedRoute represents the route associated with a component loaded in an <router-outlet>. It provides information about the route, its parameters, and related data.

• Purpose: ActivatedRoute is used to access route-specific information, such as route parameters, query parameters, data resolvers, and the route configuration itself.
• Usage: Typically injected into a component or service to access route-related information.

Key Properties and Methods of ActivatedRoute:

• params: Observable that contains the route parameters extracted from the URL.

  import { ActivatedRoute } from '@angular/router';
  
  constructor(private route: ActivatedRoute) {
    this.route.params.subscribe(params => {
      // Access route parameters
      console.log(params['id']);
    });
  }
  

• queryParamMap: Observable that contains the query parameters extracted from the URL.

  import { ActivatedRoute } from '@angular/router';
  
  constructor(private route: ActivatedRoute) {
    this.route.queryParamMap.subscribe(queryParams => {
      // Access query parameters
      console.log(queryParams.get('search'));
    });
  }
  

• data: Observable that contains static or resolved data associated with the route.

  import { ActivatedRoute } from '@angular/router';
  
  constructor(private route: ActivatedRoute) {
    this.route.data.subscribe(data => {
      // Access route data
      console.log(data['title']);
    });
  }
  

RouterState

RouterState represents the state of the router at a specific moment in time, including all active routes and their associated information.

• Purpose: RouterState provides a snapshot of the current router state, including the current route and its parent routes.
• Usage: Generally used for more advanced scenarios where you need access to the entire state of the router, including parent routes and router configuration.

Key Properties and Methods of RouterState:

• root: Returns the root ActivatedRouteSnapshot, which represents the root of the current route tree.

  import { Router, RouterStateSnapshot } from '@angular/router';
  
  constructor(private router: Router) {
    const routerState: RouterStateSnapshot = this.router.routerState;
    const root = routerState.root;
    console.log(root);
  }
  

• snapshot: Returns the current RouterStateSnapshot, which contains information about the current route and its ancestors.

  import { Router, RouterStateSnapshot } from '@angular/router';
  
  constructor(private router: Router) {
    const routerState: RouterStateSnapshot = this.router.routerState;
    const snapshot = routerState.snapshot;
    console.log(snapshot);
  }
  

• url: Returns the current URL string.

  import { Router, RouterStateSnapshot } from '@angular/router';
  
  constructor(private router: Router) {
    const routerState: RouterStateSnapshot = this.router.routerState;
    const url = routerState.url;
    console.log(url);
  }
  

Summary

• ActivatedRoute is used to access information about the current route and its parameters, query parameters, and resolved data.
• RouterState provides a snapshot of the entire router state, including the current route and its parent routes, and is used for more advanced navigation and state management scenarios.

Both ActivatedRoute and RouterState are essential in Angular applications for managing navigation, accessing route-specific data, and handling advanced routing scenarios effectively.