Conceal certain components when a user is authenticated

Question

Conceal certain components when a user is authenticated

Below is the content of my app.component.html:

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <div class='container'>
    <ul class="nav navbar-nav">
      <li class='nav-item'>
        <a class='nav-link' routerLink="/">Home</a>
      </li>
      <li class='nav-item'>
        <a class='nav-link' routerLink="/about">About</a>
      </li>
      <li class='nav-item' *ngIf='!user'>
        <a class='nav-link' routerLink="/login">Login</a>
      </li>
      <li class='nav-item' *ngIf='!user'>
        <a class='nav-link' routerLink="/register">Register</a>
      </li>
      <li class='nav-item' *ngIf='user'>
        <a class='nav-link' routerLink="/logout">Logout</a>
      </li>
    </ul>
  </div>
</nav>
<main>
  <router-outlet></router-outlet>
</main>

I am attempting to display the /logout button when the user is logged in, and hide it otherwise. Similarly, I want to show the /login and /register buttons if the user is not logged in.

This is how my login logic looks:

import {Component} from '@angular/core';
import {AuthService} from '../core/auth.service';
import {Router, Params} from '@angular/router';
import {FormBuilder, FormGroup, Validators} from '@angular/forms';

@Component({
  selector: 'page-login',
  templateUrl: 'login.component.html',
  styleUrls: ['login.scss']
})

export class LoginComponent {
  loginForm: FormGroup;
  errorMessage: string = '';

  constructor(
    public authService: AuthService,
    private router: Router,
    private fb: FormBuilder
  ) {
    this.createForm();
  }

  createForm() {
    this.loginForm = this.fb.group({
      email: ['', Validators.required],
      password: ['', Validators.required]
    });
  }

  tryFacebookLogin() {
    this.authService.doFacebookLogin()
      .then(res => {
        this.router.navigate(['/user']);
      });
  }

  tryTwitterLogin() {
    this.authService.doTwitterLogin()
      .then(res => {
        this.router.navigate(['/user']);
      });
  }

  tryGoogleLogin() {
    this.authService.doGoogleLogin()
      .then(res => {
        this.router.navigate(['/user']);
      });
  }

  tryLogin(value) {
    this.authService.doLogin(value)
      .then(res => {
        this.router.navigate(['/user']);
      }, err => {
        console.log(err);
        this.errorMessage = err.message;
      });
  }
}

An example of the doLogin function is provided below:

doLogin(value){
  return new Promise<any>((resolve, reject) => {
    firebase.auth().signInWithEmailAndPassword(value.email, value.password)
    .then(res => {
      resolve(res);
    }, err => reject(err))
  })
}

I come from an Express background and I'm relatively new to Angular. In Express, I would typically use a session variable to track whether a user is logged in or not. How can I achieve something similar in Angular?

javascript angular typescript firebase firebase-authentication

Answer 1

Answer №1

When using Firebase, you can utilize the authentication object provided by the library. Simply save the connection result into a variable for easy display.

import * as firebase from 'firebase/app';

randomFunction() {
  firebase.auth().onAuthStateChanged(user => {
    if(user) {
      this.logged = true;
    } else {
      this.logged = false;
    }
  });
}

In your HTML

<div *ngIf="logged; else #isAnonymous">
  <button>Log out</button>
</div>
<ng-template #isAnonymous>
  <button>Log in</button>
</ng-template>

Answer 2

When using Firebase, you can utilize the authentication object provided by the library. Simply save the connection result into a variable for easy display.

import * as firebase from 'firebase/app';

randomFunction() {
  firebase.auth().onAuthStateChanged(user => {
    if(user) {
      this.logged = true;
    } else {
      this.logged = false;
    }
  });
}

In your HTML

<div *ngIf="logged; else #isAnonymous">
  <button>Log out</button>
</div>
<ng-template #isAnonymous>
  <button>Log in</button>
</ng-template>

Answer 3

Answer №2

Upon further discussion in the comments of the accepted answer, it was determined that implementing a LocalStorage strategy to verify user login status would be beneficial.

To streamline the authentication process, I recommend creating a dedicated service:

auth.service.ts

import { LocalStorageService } from 'angular-2-local-storage';

@Injectable()
export class AuthService {

  constructor(private http: Http, private localStorage: LocalStorageService) { }

  login(email: string, password: string): Observable<any>{
    // Perform necessary actions;
    // Set to LocalStorage upon successful login
}

  isAuthenticated(): boolean{
    if (this.localStorage.get('isLoggedIn')){
      return true;
    }
    else{
      return false;
    }
  }

}

With this service in place, any component can easily utilize it by injecting and calling as shown below:

your.component.ts

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css']
})
export class LoginComponent implements OnInit {

  constructor(private authService: AuthService) { }
  let isLoggedIn = false;    

  ngOnInit() {
    isLoggedIn  = this.authService.isAuthenticated();

    if (isLoggedIn){
      alert('hello');
    }
  }

You can now use the isLoggedIn variable in your template with the *ngIf directive

Answer 4

Upon further discussion in the comments of the accepted answer, it was determined that implementing a LocalStorage strategy to verify user login status would be beneficial.

To streamline the authentication process, I recommend creating a dedicated service:

auth.service.ts

import { LocalStorageService } from 'angular-2-local-storage';

@Injectable()
export class AuthService {

  constructor(private http: Http, private localStorage: LocalStorageService) { }

  login(email: string, password: string): Observable<any>{
    // Perform necessary actions;
    // Set to LocalStorage upon successful login
}

  isAuthenticated(): boolean{
    if (this.localStorage.get('isLoggedIn')){
      return true;
    }
    else{
      return false;
    }
  }

}

With this service in place, any component can easily utilize it by injecting and calling as shown below:

your.component.ts

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css']
})
export class LoginComponent implements OnInit {

  constructor(private authService: AuthService) { }
  let isLoggedIn = false;    

  ngOnInit() {
    isLoggedIn  = this.authService.isAuthenticated();

    if (isLoggedIn){
      alert('hello');
    }
  }

You can now use the isLoggedIn variable in your template with the *ngIf directive

Answer 5

Answer №3

To ensure user authentication, create a variable called isLoggedIn at the component level (or utilize LocalStorage to store and access it throughout the application). Upon successful authentication of the user, toggle this variable between true and false.

Utilize *ngIf directive at the component level to show or hide specific content based on the user's login status.

Answer 6

To ensure user authentication, create a variable called isLoggedIn at the component level (or utilize LocalStorage to store and access it throughout the application). Upon successful authentication of the user, toggle this variable between true and false.

Utilize *ngIf directive at the component level to show or hide specific content based on the user's login status.

Answer 7

Answer №4

To keep track of the user's login status in your component, you can create a variable for it. When navigating to the /user route, remember to set this.isAuthenticated= true as shown below.

When logging out, ensure that you update this variable to false.

this.isAuthenticated = false;

Below is an example of how the component code might look like:

import {Component} from '@angular/core';
import {AuthService} from '../core/auth.service';
import {Router, Params} from '@angular/router';
import {FormBuilder, FormGroup, Validators} from '@angular/forms';

@Component({
  selector: 'page-login',
  templateUrl: 'login.component.html',
  styleUrls: ['login.scss']
})

export class LoginComponent {
  isAuthenticated:boolean = false;
  loginForm: FormGroup;
  errorMessage: string = '';

  constructor(
    public authService: AuthService,
    private router: Router,
    private fb: FormBuilder
  ) {
    this.createForm();
  }

  createForm() {
    this.loginForm = this.fb.group({
      email: ['', Validators.required],
      password: ['', Validators.required]
    });
  }

  tryFacebookLogin() {
    this.authService.doFacebookLogin()
      .then(res => {
        this.isAuthenticated = true;
        this.router.navigate(['/user']);
      });
  }

  tryTwitterLogin() {
    this.authService.doTwitterLogin()
      .then(res => {
      this.isAuthenticated = true;
        this.router.navigate(['/user']);
      });
  }

  tryGoogleLogin() {
    this.authService.doGoogleLogin()
      .then(res => {
      this.isAuthenticated = true;
        this.router.navigate(['/user']);
      });
  }

  tryLogin(value) {
    this.authService.doLogin(value)
      .then(res => {
        this.isAuthenticated = true;
        this.router.navigate(['/user']);
      }, err => {
        this.isAuthenticated = false;
        console.log(err);
        this.errorMessage = err.message;
      });
  }

  logOut(){
    //write logout logic from server here
    this.isAuthenticated = false;
  }
}

On your template, you can display different buttons based on the authentication status:

<div *ngIf="isAuthenticated>Show Logout button</div>
<div *ngIf="!isAuthenticated">Show Login button</div>

Answer 8

To keep track of the user's login status in your component, you can create a variable for it. When navigating to the /user route, remember to set this.isAuthenticated= true as shown below.

When logging out, ensure that you update this variable to false.

this.isAuthenticated = false;

Below is an example of how the component code might look like:

import {Component} from '@angular/core';
import {AuthService} from '../core/auth.service';
import {Router, Params} from '@angular/router';
import {FormBuilder, FormGroup, Validators} from '@angular/forms';

@Component({
  selector: 'page-login',
  templateUrl: 'login.component.html',
  styleUrls: ['login.scss']
})

export class LoginComponent {
  isAuthenticated:boolean = false;
  loginForm: FormGroup;
  errorMessage: string = '';

  constructor(
    public authService: AuthService,
    private router: Router,
    private fb: FormBuilder
  ) {
    this.createForm();
  }

  createForm() {
    this.loginForm = this.fb.group({
      email: ['', Validators.required],
      password: ['', Validators.required]
    });
  }

  tryFacebookLogin() {
    this.authService.doFacebookLogin()
      .then(res => {
        this.isAuthenticated = true;
        this.router.navigate(['/user']);
      });
  }

  tryTwitterLogin() {
    this.authService.doTwitterLogin()
      .then(res => {
      this.isAuthenticated = true;
        this.router.navigate(['/user']);
      });
  }

  tryGoogleLogin() {
    this.authService.doGoogleLogin()
      .then(res => {
      this.isAuthenticated = true;
        this.router.navigate(['/user']);
      });
  }

  tryLogin(value) {
    this.authService.doLogin(value)
      .then(res => {
        this.isAuthenticated = true;
        this.router.navigate(['/user']);
      }, err => {
        this.isAuthenticated = false;
        console.log(err);
        this.errorMessage = err.message;
      });
  }

  logOut(){
    //write logout logic from server here
    this.isAuthenticated = false;
  }
}

On your template, you can display different buttons based on the authentication status:

<div *ngIf="isAuthenticated>Show Logout button</div>
<div *ngIf="!isAuthenticated">Show Login button</div>

Conceal certain components when a user is authenticated

Answer №1

Answer №2

Answer №3

Answer №4

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