(TypeError: Cannot read property 'length' of null at HttpHeaders.applyUpdate) Angular 5, Http Client

Question

I\'m getting this reponse when making an http request in service.

Here\'s the Login component

export class LoginComponent {
  credentials: Credentials;
         


        

Answer 1

try like this :

service.ts

login(credentials): Observable {
    return this.http.post("http://localhost:3000/api/Users/login", {
        username: credentials.username,
        password: credentials.password
    }).map(data => data.json())
}

component.ts

onLogin(credentials) {
    this.userService.login(credentials)
        .subscribe(data => {
            console.log('data', data);
        }, (error) => {
            console.log('error', error);
        })
}