Angular Routing: Enhance User Experience with Scroll to Top on Navigation

By default, Angular doesn't automatically scroll to the top of the page when you navigate between routes. This can lead to a disjointed user experience if they were scrolled down on the previous page.

Approaches:

1. Using RouterModule (Angular 6.1 and later):

2. Manual Approach (for older Angular versions or more control):

   • Inside the subscription callback, use window.scrollTo(0, 0) to scroll to the top (0, 0 coordinates).

     import { Component, OnInit } from '@angular/core';
     import { Router } from '@angular/router';
     
     @Component({
       selector: 'app-my-component',
       templateUrl: './my-component.component.html',
       styleUrls: ['./my-component.component.css']
     })
     export class MyComponent implements OnInit {
     
       constructor(private router: Router) { }
     
       ngOnInit() {
         this.router.events.pipe(
           filter(event => event instanceof NavigationEnd)
         ).subscribe(() => {
           window.scrollTo(0, 0);
         });
       }
     }
     

Choosing the Right Approach:

• For simplicity and compatibility with newer Angular versions, use the RouterModule approach.
• For more control over scrolling behavior or if you're using older Angular versions, consider the manual approach.

Additional Considerations:

• If you have a fixed header or other elements that affect the scroll position, you might need to adjust the vertical offset accordingly in the window.scrollTo call.
• Consider using a smooth scrolling animation library or technique for a more user-friendly experience.

import { RouterModule, Routes } from '@angular/router';

const appRoutes: Routes = [
  // ... your routes
];

@NgModule({
  imports: [RouterModule.forRoot(appRoutes, { scrollPositionRestoration: 'enabled' })],
  exports: [RouterModule]
})
export class AppRoutingModule { }

Explanation:

This code configures the RouterModule with the scrollPositionRestoration: 'enabled' option. This tells Angular to automatically manage scroll position when navigating between routes, ensuring it starts at the top each time.

my-component.component.ts:

import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent implements OnInit {

  constructor(private router: Router) { }

  ngOnInit() {
    this.router.events.pipe(
      filter(event => event instanceof NavigationEnd)
    ).subscribe(() => {
      window.scrollTo(0, 0);
    });
  }
}

1. The component injects the Router service.
2. In ngOnInit, it subscribes to the router.events observable.
3. The filter operator ensures only NavigationEnd events are processed, signifying successful navigation completion.

If you're using Angular Material in your project, you can leverage the MatScrollDispatcher service. This service provides methods to interact with scrollable elements in your application.

Here's an example:

import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { MatScrollDispatcher } from '@angular/material/cdk/scrolling';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent implements OnInit {

  constructor(private router: Router, private scrollDispatcher: MatScrollDispatcher) { }

  ngOnInit() {
    this.router.events.pipe(
      filter(event => event instanceof NavigationEnd)
    ).subscribe(() => {
      this.scrollDispatcher.scrollToTop(); // Scrolls to top of the scrollable element
    });
  }
}

• We inject the MatScrollDispatcher service into the component.
• The scrollToTop() method of the scrollDispatcher scrolls the currently registered scrollable element to the top.

Note: This method requires Angular Material and assumes you have a scrollable element managed by the MatScrollDispatcher.

Using a Custom Directive:

You can create a custom directive that listens for route changes and triggers the scrolling behavior. This approach offers more flexibility if you have specific scrolling requirements or conditions.

Here's a basic example (structure):

scroll-to-top.directive.ts:

import { Directive, ElementRef, HostListener, OnInit } from '@angular/core';
import { Router } from '@angular/router';

@Directive({
  selector: '[appScrollToTop]'
})
export class ScrollToTopDirective implements OnInit {

  constructor(private elementRef: ElementRef, private router: Router) { }

  ngOnInit() {
    // Optional: Check if the element is scrollable here
  }

  @HostListener('routerNavigationEnd') onRouteChange() {
    // Scroll to top logic (e.g., elementRef.nativeElement.scrollTop = 0)
  }
}

• The directive targets elements with the appScrollToTop attribute.
• It listens for the routerNavigationEnd event (custom event you can emit from your component).
• In the event listener, implement the desired scrolling behavior (e.g., using elementRef.nativeElement.scrollTop).