Angular2 beta getting exception “No provider for Router! (RouterLink -> Router)”

angularangular2-routingtypescript

I have been banging my head against this for two days now. I am trying to implement some simple routing in Angular2 beta0.0.2. Please note that I am using typescript.

So what I understand is that I need to bootstrap my root app component with ROUTER_PROVIDERS so that these services are available to my who app AND set the directives for the components that want to implement routing to ROUTER_DIRECTIVES.

Here is what I have:

//ANGULAR  ******************************
import {provide, Component} from 'angular2/core';
import {bootstrap} from 'angular2/platform/browser';
import {
        APP_BASE_HREF,
        ROUTER_DIRECTIVES,
        ROUTER_PROVIDERS,
        HashLocationStrategy,
        LocationStrategy,
        RouteConfig,
        } from 'angular2/router';

//COMPONENTS  ******************************
import {ShiftCalendarComponent} from './components/calendar/shift-calendar.component';
import {ShiftAdminComponent} from './components/admin/shift-admin.component';
import {ShiftListComponent} from './components/shifts/shift-list.component';

//CLASS  ******************************
@Component({
    selector: 'shift-app',
    directives: [ROUTER_DIRECTIVES],
    template: `<div>
                 <nav>
                     <h3> Navigation: </h3>
                     <ul>
                         <li><a [routerLink]="['Calendar']" > Home </a></li>
                         <li><a [routerLink]="['Admin']" > About </a></li>
                         <li><a [routerLink]="['Shifts']" > Contact us </a></li>
                     </ul>
                 </nav>            
                 <router-outlet></router-outlet>
             </div>`
})
@RouteConfig([
    { path: '/', name: 'root', redirectTo: ['/Calendar'] },
    { path: '/calendar', name: 'Calendar', component: ShiftCalendarComponent },
    { path: '/admin', name: 'Admin', component: ShiftAdminComponent },
    { path: '/shifts', name: 'Shifts', component: ShiftListComponent }
])
export class ShiftApp { } 

//BOOTSTRAP   ******************************
    bootstrap(ShiftApp, [
        ROUTER_PROVIDERS, 
        provide(LocationStrategy, { useClass: HashLocationStrategy }),
        provide(APP_BASE_HREF, { useValue: '/' })    
    ]);

The angular app loads and the template is displayed, but no link works and I get the following error in my console:

EXCEPTION: No provider for Router! (RouterLink -> Router) angular2.dev.js

In my index.html (which i call view.html) I have linked to all the relevant libraries and have included router.dev.js and the sources tab of my console shows me that all the needed scripts are successfully loaded.

I have read about every stack overflow question with router link errors for Angular2 and the entire router docs but cannot find why mine is not working. As far as I can tell my code matches the Angular2 Documentation

This documentation shows that the ROUTER_DIRECTIVES includes the directives like RouterOutlet and RouterLink

Question?

If I am successfully setting the directives for the component to ROUTER_DIRECTIVES, why am I getting the "No provider for Router! RouterLink" error?

Best Answer

Move your bootstrapping process into s separate file:

import {bootstrap} from 'angular2/platform/browser';
import {provide, Component} from 'angular2/core';
import {ShiftApp} from './app.component';

import {
    APP_BASE_HREF,
    ROUTER_DIRECTIVES,
    ROUTER_PROVIDERS,
    HashLocationStrategy,
    LocationStrategy
} from 'angular2/router';

bootstrap(ShiftApp, [
    ROUTER_PROVIDERS,
    provide(LocationStrategy, { useClass: HashLocationStrategy }),
    provide(APP_BASE_HREF, { useValue: '/' })
]);

Import that new file in your index.html:

System.config({
    packages: {
        app: {
            format: 'register',
            defaultExtension: 'js'
        }
    }
});
System.import('app/boot')
    .then(null, console.error.bind(console));

Advantages of doing that can be found here.

Also as mentioned in the comment, bootstrap your root component instead of a child component.

Update (Angular 6 +)

The recommended way to create a singleton service has changed. It is now recommended to specify in the @Injectable decorator on the service that it should be provided in the 'root'. This makes a lot of sense to me and there's no need to list all the provided services in your modules at all anymore. You just import the services when you need them and they register themselves in the proper place. You can also specify a module so it will only be provided if the module is imported.

@Injectable({
  providedIn: 'root',
})
export class ApiService {
}

Update (Angular 2)

With NgModule, the way to do it now I think is to create a 'CoreModule' with your service class in it, and list the service in the module's providers. Then you import the core module in your main app module which will provide the one instance to any children requesting that class in their constructors:

CoreModule.ts

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { ApiService } from './api.service';

@NgModule({
    imports: [
        CommonModule
    ],
    exports: [ // components that we want to make available
    ],
    declarations: [ // components for use in THIS module
    ],
    providers: [ // singleton services
        ApiService,
    ]
})
export class CoreModule { }

AppModule.ts

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { AppComponent } from './app.component';
import { CoreModule } from './core/core.module';

@NgModule({
    declarations: [ AppComponent ],
    imports: [
        CommonModule,
        CoreModule // will provide ApiService
    ],
    providers: [],
    bootstrap: [ AppComponent ]
})
export class AppModule { }

Original Answer

If you list a provider in bootstrap(), you don't need to list them in your component decorator:

import { ApiService } from '../core/api-service';

@Component({
    selector: 'main-app',
    templateUrl: '/views/main-app.html',
    // DO NOT LIST PROVIDERS HERE IF THEY ARE IN bootstrap()!
    // (unless you want a new instance)
    //providers: [ApiService]
})
export class MainAppComponent {
    constructor(private api: ApiService) {}
}

In fact listing your class in 'providers' creates a new instance of it, if any parent component already lists it then the children don't need to, and if they do they will get a new instance.

Question?

Best Answer

Related Solutions

Angular2 Component Router basic issue

Angular – How to create a singleton service in Angular 2

Update (Angular 6 +)

Update (Angular 2)

CoreModule.ts

AppModule.ts

Original Answer

Related Topic