Dynamically add meta description based on route in Angular

Question

I'm using Angular 5 to build a small brochure type website. Thus far, I have my routes set up, and the page title changes dynamically based on the activated route. I got this working using the instructions on this blog: https://toddmotto.com/dynamic-page-titles-angular-2-router-events

I'm currently storing my routes and titles in app.module.ts as such:

imports: [
    BrowserModule,
    RouterModule.forRoot([
      { 
        path: '', 
        component: HomeComponent,
        data: {
          title: 'Home'
        }
      },
      { 
        path: 'about', 
        component: AboutComponent,
        data: {
          title: 'About'
        } 
      },
      { 
        path: 'products-and-services', 
        component: ProductsServicesComponent,
        data: {
          title: 'Products & Services'
        }  
      },
      { 
        path: 'world-class-laundry', 
        component: LaundryComponent,
        data: {
          title: 'World Class Laundry'
        }  
      },
      { 
        path: 'contact', 
        component: ContactComponent,
        data: {
          title: 'Contact'
        }  
      },
      { 
        path: '**', 
        component: NotFoundComponent,
        data: {
          title: 'Page Not Found'
        }  
      }
    ])
  ],

I'd like to store my meta descriptions there as well, if adding them under data: would be easy enough.

I'm pulling in that title data with the following code, which is noted in the blog link above:

ngOnInit() {
    this.router.events
      .filter((event) => event instanceof NavigationEnd)
      .map(() => this.activatedRoute)
      .map((route) => {
        while (route.firstChild) route = route.firstChild;
        return route;
      })
      .filter((route) => route.outlet === 'primary')
      .mergeMap((route) => route.data)
      .subscribe((event) => {
        this.titleService.setTitle(event['title']);
      });
  }

So my question is, is there a way to dynamically set the meta description using the same method? If there is a way to combine the page title and meta description function, that would be ideal.

I have very limited Angular training, so this might be a nooby question. I'm more of a designer/css/html kind of guy.

Answer 1

First create a SEOService or Something like below:

import {Injectable} from '@angular/core'; 
import { Meta, Title } from '@angular/platform-browser';

@Injectable()
export class SEOService {
  constructor(private title: Title, private meta: Meta) { }


  updateTitle(title: string) {
    this.title.setTitle(title);
  }

  updateOgUrl(url: string) {
    this.meta.updateTag({ name: 'og:url', content: url })
  }

  updateDescription(desc: string) {
    this.meta.updateTag({ name: 'description', content: desc })
  }

After injecting the SEOService in your component, set meta tags and title in OnInit method

ngOnInit() {
    this.router.events.pipe(
       filter((event) => event instanceof NavigationEnd),
       map(() => this.activatedRoute),
       map((route) => {
         while (route.firstChild) route = route.firstChild;
         return route;
       }),
       filter((route) => route.outlet === 'primary'),
       mergeMap((route) => route.data)
      )
      .subscribe((event) => {
        this._seoService.updateTitle(event['title']);
        this._seoService.updateOgUrl(event['ogUrl']);
        //Updating Description tag dynamically with title
        this._seoService.updateDescription(event['title'] + event['description'])
      }); 
    }

Then configure your routes like

      { 
        path: 'about', 
        component: AboutComponent,
        data: {
          title: 'About',
          description:'Description Meta Tag Content',
          ogUrl: 'your og url'
        } 
      },

IMHO this is a clear way of dealing with meta tags. You can update facebook and twitter specific tags easier.