peertube/client/src/app/login/login.component.ts

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { Router } from '@angular/router';

import { AuthService, FormReactive } from '../shared';

@Component({
  selector: 'my-login',
  templateUrl: './login.component.html'
})

export class LoginComponent extends FormReactive implements OnInit {
  error: string = null;

  form: FormGroup;
  formErrors = {
    'username': '',
    'password': ''
  };
  validationMessages = {
    'username': {
      'required': 'Username is required.',
    },
    'password': {
      'required': 'Password is required.'
    }
  };

  constructor(
    private authService: AuthService,
    private formBuilder: FormBuilder,
    private router: Router
  ) {
    super();
  }

  buildForm() {
    this.form = this.formBuilder.group({
      username: [ '', Validators.required ],
      password: [ '', Validators.required ],
    });

    this.form.valueChanges.subscribe(data => this.onValueChanged(data));
  }

  ngOnInit() {
    this.buildForm();
  }

  login() {
    this.error = null;

    const { username, password } = this.form.value;

    this.authService.login(username, password).subscribe(
      result => this.router.navigate(['/videos/list']),

      error => {
        console.error(error.json);

        if (error.json.error === 'invalid_grant') {
          this.error = 'Credentials are invalid.';
        } else {
          this.error = `${error.json.error}: ${error.json.error_description}`;
        }
      }
    );
  }
}