I'm getting this reponse when making an http request in service.
Here's the Login component
export class LoginComponent {
credentials: Credentials;
constructor(
private auth: AuthService,
@Inject(UserService) private userService: UserService,
@Inject(HttpClient) private http: HttpClient,
private auth0: Auth0Service
) {}
onLogin(credentials) {
const sendReq = this.userService.login(credentials);
}
I've added UserService in providers in App.module
Here's the UserService
@Injectable()
export class UserService {
constructor(
@Inject(Auth0Service) private authService: Auth0Service,
protected http: HttpClient // @Inject(HttpClient) protected http: HttpClient
) {}
login(credentials): Observable<any> {
console.log(credentials);
console.log(credentials.username);
this.http
.post("http://localhost:3000/api/Users/login", {
username: credentials.username,
password: credentials.password
})
.subscribe(
data => {
console.log(data);
},
err => {
console.log("Something went wrong!");
console.log(err);
}
);
return credentials;
// this.auth.login(credentials);
}
}
Here's the console
at MergeMapSubscriber._innerSub (mergeMap.js:138)
user.service.ts:14
{username: "hamzakpt", password: "hamza"}
user.service.ts:15
hamzakpt
user.service.ts:26 Something went wrong!
user.service.ts:27
TypeError: Cannot read property 'length' of null
at HttpHeaders.applyUpdate (http.js:308)
at eval (http.js:255)
at Array.forEach (<anonymous>)
at HttpHeaders.init (http.js:255)
at HttpHeaders.forEach (http.js:354)
at Observable.eval [as _subscribe] (http.js:2153)
at Observable._trySubscribe (Observable.js:172)
at Observable.subscribe (Observable.js:160)
at subscribeToResult (subscribeToResult.js:23)
at MergeMapSubscriber._innerSub (mergeMap.js:138)
The same get request works in LoginComponent but not in UserService. UserService is global service while Login is in a different module.
I've also added HTTPClientModule in app.module and Login Module.
Problem: This problem may occur due to null value in header i.e.
cloned = req.clone({
headers: req.headers.append('token', token) // i.e. token is null
})
Solution: to fix this, check variable before setting into header i.e.
if (token) {
cloned = req.clone({
headers: req.headers.append('token', token)
})
}