Angular 4+ routing breadcrumbs
npm install ngx-breadcrumbsbash
install via npm
$ npm --save install ngx-breadcrumbs
`
bash
install via yarn
$ yarn add ngx-breadcrumbs
`Usage
Import the
in your root module (app.module.ts) after
importing the _router_ module. `javascript
import { RouterModule } from '@angular/router';
import { McBreadcrumbsModule } from 'ngx-breadcrumbs';@NgModule({
imports: [
RouterModule.forRoot(myRoutes),
McBreadcrumbsModule.forRoot()
],
})
export class AppModule {}
`Place the
component, which will render the breadcrumbs,
somewhere in your markup.`javascript
@Component({
selector: 'app-root',
template:
})
export class AppComponent {}
Usage of the
render component is optional. If a different
markup output is desired, a custom component can be created that subscribes to
the McBreadcrumbsService.crumbs$ observable. $3
Breadcrumbs links are generated based on the route configuration. If a route
entry contains a
data.breadcrumbs property the _breadcrumbs service_ assumes
breadcrumbs should be created whenever this route or one its child routes are
active. `javascript
const myRoutes : Route[] = {
{
path: '',
component: HomeComponent,
data: {
// Uses static text (Home)
breadcrumbs: 'Home'
}
},
{
path: 'about',
component: AboutComponent,
data: {
// Uses last urlfragment (about) as text
breadcrumbs: true
}
},
{
path: 'person',
data: {
// Uses text property (Person)
breadcrumbs: true,
text: 'Person'
},
children: [
{
path: '',
component: PersonListComponent
},
{
path: ':id',
component: PersonDetailComponent,
data: {
// Interpolates values resolved by the router
breadcrumbs: '{{ person.name }}'
},
resolve: {
person: PersonResolver
}
}
]
},
{
path: 'folder',
data: {
// Uses static text 'Folder'
breadcrumbs: 'Folder'
},
children: [
{
path: '',
component: FolderComponent
},
{
path: ':id',
component: FolderComponent,
data: {
// Resolves the breadcrumbs for this route by
// implementing a McBreadcrumbsResolver class.
breadcrumbs: FolderBreadcrumbsResolver
}
}
]
}
};
`$3
#### IBreadcrumb
The IBreadcrumb interface defines the properties of the breadcrumb items.
javascript
export interface IBreadcrumb {
text: string, // The text to display
path: string // The associated path
}
`#### McBreadcrumbsComponent
The component simply renders the list of the
items
provided by the McBreadcrumbsService. The HTML output matches that of
Bootstrap 4 markup. A custom breadcrumb component is easily created by injecting the breadcrumb
service and iterating over the breadcrumb items.
#### McBreadcrumbsService
The service has one public property
crumbs$. It's an observable stream of
IBreadcrumb[], which is updated after each route change. #### McBreadcrumbsResolver
If needed, a custom resolver can be implemented which is activated whenever a
certain route becomes active. This can be useful whenever the route
configuration cannot match the desired breadcrumb hierachy.
The signature of the resolver implements
Resolve from the
Angular Router and needs to resolve an
array of IBreadcrumb items. To associate a route with a certain resolver, it breadcrumbs data property in
the route configuration should point to the resolver:
`javascript
const myRoutes = [
{
path: 'somepath',
component: SomeComponent,
data: {
breadcrumbs: MyBreadcrumbsResolver
}
}
];
`##### Members
javascript
// Should resolve zero or more IBreadcrumb items.
function resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot)
: Observable|Promise|T
`javascript
// Helper function that returns the full path for the provided route snapshot.
function getFullPath(route: ActivatedRouteSnapshot)
: string
`##### Example
javascript
@Injectable()
export class MyBreadcrumbsResolver inherits McBreadcrumbsResolver { // Optional: inject any required dependencies
constructor(private myService: MyService) {}
resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
const myFolderId = route.params.id;
const myCrumbs =
this.myService.getFolders(myFolderId)
.map((folder) => ({
text: folder.title,
path: super.getFullPath(route.parent) + '/' + folder.id
});
// Note: the resolve method can return any of the following types:
//
// * IBreadcrumb[]
// * Observable
// * Promise
return myCrumbs;
}
}
`#### McBreadcrumbsConfig
The configuration of the breadcrumbs module.
##### Members
postProcess
Callback function with the following signature:
javascript
function (crumbs: IBreadcrumb[]) : Promise | Observable | IBreadcrumb[];
`Can be used to make custom changes to the breadcrumb array after the service
has constructed the breadcrumb trail.
Example:
javascript
@NgModule({
/ ... /
})
export class AppModule {
constructor(breadcrumbsConfig: McBreadcrumbsConfig) { breadcrumbsConfig.postProcess = (x) => {
// Ensure that the first breadcrumb always points to home
let y = x;
if(x.length && x[0].text !== 'Home') {
y = [
{
text: 'Home',
path: ''
}
].concat(x);
}
return y;
};
}
}
``