login.component.ts

import { Component, OnInit, NgZone } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { first } from 'rxjs/operators';

import { AuthenticationService } from '../../services/authentication.service';
import { AlertService } from '../../services/alert.service';
import { CookieService } from 'ngx-cookie-service';

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css']
})
export class LoginComponent implements OnInit {
    loginForm: FormGroup;
    loading = false;
    submitted = false;
    returnUrl: string;
    get frm() { return this.loginForm.controls; }

    constructor(
        private formBuilder: FormBuilder,
        private route: ActivatedRoute,
        private router: Router,
        private authenticationService: AuthenticationService,
        private alertService: AlertService,
        private zone: NgZone,
        private cookieService : CookieService 
        ) {

            if(cookieService.get('remember')) {
               this.frm.username.setValue(this.cookieService.get('username'));
               this.frm.RememberMe.setValue(this.cookieService.get('remember'));
            }
        
          }
    ngOnInit() {
        this.loginForm = this.formBuilder.group({
            username: ['', Validators.required],
            password: ['', Validators.required],
            RememberMe: ['']
        });

        this.authenticationService.logout();

        this.returnUrl = this.route.snapshot.queryParams['returnUrl'] || '/';
    }

    onSubmit() {
        this.submitted = true;

        if (this.loginForm.invalid) {
            return;
        }

        this.loading = true;
        this.authenticationService.login(this.frm.username.value, this.frm.password.value)
            .pipe(first())
            .subscribe(
                data => {
                    this.cookieService.set('username', this.frm.username.value);
                    this.cookieService.set('remember', this.frm.RememberMe.value);
                    this.zone.run(() => this.router.navigate(['../']));
                },
                error => {
                    this.alertService.error(error);
                    this.loading = false;
                });
    }
}