How can I create breadcrumb in Angular

Question

I want to add breadcrumb to my page. I have many routes and none of them have children.

I tried to do it by creating a child, but there are too many redirects to common pages. For example;

Home > Library > Lessons > Lesson Name

Assigned Lessons > Lesson Name

When the route of the course names is the same, how should I child them or is there a way to do it without following the route?

I tried to do it according to the route, the result I expected was;

Home > Library > Lessons > Lesson Name Assigned Lessons > Lesson Name

But when I do it, when it comes to the lesson name, it automatically happens like this;

Home > Library > Lessons > Lesson Name

Answer 1

Here's a simple way to add breadcrumbs in Angular:

1. Create a Breadcrumb Service:

// breadcrumb.service.ts
import { Injectable } from '@angular/core';
import { ActivatedRoute, NavigationEnd, Router } from '@angular/router';
import { filter } from 'rxjs/operators';

@Injectable({
  providedIn: 'root',
})
export class BreadcrumbService {
  breadcrumbs: Array<{ label: string, url: string }> = [];

  constructor(private router: Router, private activatedRoute: ActivatedRoute) {
    this.router.events.pipe(
      filter(event => event instanceof NavigationEnd)
    ).subscribe(() => {
      this.breadcrumbs = this.createBreadcrumbs(this.activatedRoute.root);
    });
  }

  private createBreadcrumbs(route: ActivatedRoute, url: string = '', breadcrumbs: Array<{ label: string, url: string }> = []): Array<{ label: string, url: string }> {
    const children: ActivatedRoute[] = route.children;

    if (children.length === 0) {
      return breadcrumbs;
    }

    for (const child of children) {
      const routeURL: string = child.snapshot.url.map(segment => segment.path).join('/');
      if (routeURL !== '') {
        url += `/${routeURL}`;
      }

      breadcrumbs.push({ label: child.snapshot.data['breadcrumb'], url: url });
      return this.createBreadcrumbs(child, url, breadcrumbs);
    }

    return breadcrumbs;
  }
}

2. Set Breadcrumb Data in Your Routes:

// app-routing.module.ts
const routes: Routes = [
  {
    path: 'home',
    component: HomeComponent,
    data: { breadcrumb: 'Home' },
  },
  {
    path: 'library',
    component: LibraryComponent,
    data: { breadcrumb: 'Library' },
    children: [
      {
        path: 'lessons',
        component: LessonsComponent,
        data: { breadcrumb: 'Lessons' },
        children: [
          {
            path: ':lessonName',
            component: LessonDetailComponent,
            data: { breadcrumb: 'Lesson Name' },
          },
        ],
      },
      // Other library routes...
    ],
  },
  // Other routes...
];

3. Display Breadcrumbs in Your Component:

// breadcrumb.component.ts
import { Component, OnInit } from '@angular/core';
import { BreadcrumbService } from './breadcrumb.service';

@Component({
  selector: 'app-breadcrumb',
  templateUrl: './breadcrumb.component.html',
  styleUrls: ['./breadcrumb.component.css'],
})
export class BreadcrumbComponent implements OnInit {
  breadcrumbs: Array<{ label: string, url: string }> = [];

  constructor(private breadcrumbService: BreadcrumbService) {}

  ngOnInit(): void {
    this.breadcrumbs = this.breadcrumbService.breadcrumbs;
  }
}

4. Use Breadcrumb Component in Your Layout:

<!-- app.component.html -->
<app-breadcrumb></app-breadcrumb>
<router-outlet></router-outlet>

5. Create Breadcrumb Template: Create a template for displaying breadcrumbs.

<!-- breadcrumb.component.html -->
<nav>
  <ng-container *ngFor="let breadcrumb of breadcrumbs; let last = last">
    <ng-container *ngIf="!last">
      <a [routerLink]="breadcrumb.url">{{ breadcrumb.label }}</a> &gt;
    </ng-container>
    <ng-container *ngIf="last">
      {{ breadcrumb.label }}
    </ng-container>
  </ng-container>
</nav>