“No provider for AuthGuard!” using CanActivate in Angular 2

Question

EDIT : Obviously this is outdated, now you provide your guard at the providers array in an NgModule. Watch other answers or official documentation

Answer 1

Also, don't fall into the trap of using a literal for the guard class inside your routing configuration, just because some blog articles do:

{ path: 'whatever', component: WhatEverComponent, canActivate: ['WhatEverGuard'] }

is not going to work (No provider for...), instead, use the class directly:

{ path: 'whatever', component: WhatEverComponent, canActivate: [WhatEverGuard] }

Another hint, when lazy loading components, the guard is applied in the routing configuration of the parent component, not in the routing configuration of the lazy loaded component.

Answer 2

Since you got the solution as it was due to syntax issue. I just wanted to share this info.

we need to provide the AuthGaudSerivce as provider in only that module that correspond to respective route. No need to provide in main module or root module as main module will automatically load all the given sub module.This helps in keeping the code modular and encapsulated.

for example, suppose we have below scenario

1. we have module m1
2. we have route m1r in module m1
3. route m1r has 2 route r1 and r2
4. we want to protect r1 using authGaurd
5. finally we have main module that is dependent on sub module m1 

Below is just prototype, not the actual code for understanding purpose

//m1.ts    
import {AuthGaurd} from './auth.gaurd.service'
import {m1r} from './m1r'
    @NgModule(
     imports: [m1r],
     providers: [AuthGaurd]
    )
    export class m1{
    }

//m1r.ts
import {AuthGaurd} from './auth.gaurd.service'
const authRoute = [
 {path: '/r1', component: 'authComponent', canActivate: [AuthGaurd]},
 {path: '/r2', component: 'other'}
]
export authRoute

//main.module.ts
import {m1} from ''
import {mainComponent} from ''
@NgModule({
  imports: [m1],
  bootstrap: [mainComponent]
  })
export class MainModule{}    

Answer 3

you can try import AuthGuard in provider of that module and then import it in the routing component-routing.module.ts file also

@NgModule({
providers: [
    AuthGuard
  ],})

Answer 4

Try to add

@Injectable({ providedIn: 'root' }) no need to add to module provider.

Answer 5

I had this same issue after going through the Route Guards section of Routing and Authorization tutorial on the Angular website https://angular.io/docs/ts/latest/guide/router.html, it is section 5.

I am adding AuthGuard to one of my main routes and not to child routes like the tutorial shows.

I fixed it by added AuthGuard to my list of providers in my app.module.ts file, so that file now looks like this:

import { AppComponent } from './app.component';
import {AppRoutingModule} from './app-routing.module';
import {AuthGuard} from './auth-gaurd.service';

import { AnotherPageComponent } from './another-page/another-page.component';
import { LoginPageComponent } from './login-page/login-page.component';

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    JsonpModule,
    AppRoutingModule,
    HttpModule
  ],
  declarations: [
    AppComponent,
    LoginPageComponent,
    AnotherPageComponent
  ],
  providers: [AuthGuard],
  bootstrap: [AppComponent]
})

export class AppModule { }

I have gone back through the tutorial and in their app.module.ts file, they do not add AuthGuard to the providers, not sure why.

Answer 6

I encountered this issue when I was following a tutorial. I tried most of the answer here but not getting any success. Then I tried the silly way like putting the AuthGuard before the other services in the provider and it works.

// app.module.ts

 .. 
 providers: [
   AuthGuard,
   UserService,
   ProjectService
  ]