Can't resolve all parameters for AuthGuard: In my AuthGuard service

Question

I have a code for AuthGuard.service.ts as follows.

import { Injectable } from '@angular/core';
import { ActivatedRoute, CanActivate } from '@angular/router';
import { userLoginService } from './userLoginService';
export class AuthGuard implements CanActivate {
    constructor(private service: userLoginService) { }
    canActivate() {
        if (this.service.IsloggedIn()) {
            return true;
        } else {
            window.alert(' You are not logged in.Please LogIn ');
            return false;
        }
    }

}

In userLoginService.ts, I have code as follows

export class userLoginService {
    constructor() {}
    IsloggedIn(): boolean {
        return false;
    }
}

I am injecting this AuthGuard.service.ts in my route as follows. And I have also provided this service name in providers of NgModule.

    const appRoutes: Routes = [
      { path: '', component: HomePageComponent, pathMatch: 'full' },
      { path: 'CartItems', component: CartItemsComponent, pathMatch: 'full', canActivate: [ AuthGuard ]},
    ];
@NgModule({
.
.
.
 providers: [UserInfoService , AuthGuard],
.
.
.

Now when executing this code I am getting an error as follows.

Uncaught Error: Can't resolve all parameters for AuthGuard: (?).
    at syntaxError (compiler.js:466)
    at CompileMetadataResolver._getDependenciesMetadata (compiler.js:15547)
    at CompileMetadataResolver._getTypeMetadata (compiler.js:15382)
    at CompileMetadataResolver._getInjectableMetadata (compiler.js:15362)
    at CompileMetadataResolver.getProviderMetadata (compiler.js:15722)
    at eval (compiler.js:15633)
    at Array.forEach (<anonymous>)
    at CompileMetadataResolver._getProvidersMetadata (compiler.js:15593)
    at CompileMetadataResolver.getNgModuleMetadata (compiler.js:15161)
    at JitCompiler._loadModules (compiler.js:33542)

Would you please let me know where I have committed a mistake.

And where do you provide the `UserLoginService`? Is it even `@Injectable`? — jonrsharpe, Dec 06 '17 at 17:04
can you add the entire file for the routes (with imports) @roopteja — Alejandro Lora, Dec 06 '17 at 17:08
But you aren't actually *showing that*, or its inclusion in the module. Give a [mcve]. — jonrsharpe, Dec 06 '17 at 17:09
I have not given the import statement correctly. It is working fine now. Sorry for the disturbance. And Thank You for the help. — roopteja, Dec 06 '17 at 17:10
@jonrsharpe Sorry for the disturbance. It is my bad. Thank You for the help. I will make sure that I will not do like this again. — roopteja, Dec 06 '17 at 17:11

score 32 · Answer 1 · edited Jan 11 '20 at 16:55

32

I see you import Injectable but you never use it !!

In your AuthGuard.service.ts. you should add : @Injectable() above your class as like :

@Injectable()
export class AuthGuard implements CanActivate {
    ...
}

edited Jan 11 '20 at 16:55

Community

1
1

answered Dec 26 '17 at 00:27

Paris Benamour

327
2
3

score 0 · Answer 2 · edited Jan 09 '20 at 05:25

Uncaught Error: Can't resolve all parameters for AuthGuard: (?). at syntaxError (compiler.js:431) at CompileMetadataResolver._getDependenciesMetadata ..............

I'm facing this problem too long and just solve this error by following.

Please add those two line in your 'app.component.ts' and your problem will be solved.

    import 'core-js/es6/reflect';

    import 'core-js/es7/reflect';

score 0 · Answer 3 · answered Mar 12 '20 at 16:53

0

In my case, I moved guard file to another directory. Re ng serve solved my problem.

answered Mar 12 '20 at 16:53

Richard

556
5
12

Can't resolve all parameters for AuthGuard: In my AuthGuard service

3 Answers3