ReferenceError: localStorage is not defined

Question

I am trying to make User Authentication with Angular and ASP.NET Core.

I am following the tutorial found here:

https://fullstackmark.com/post/10/user-authentication-with-angular-and-asp-net-core

I followed all the steps with no errors.

The app runs, but when I go to "/register" or "/login" routes, I get

NodeInvocationException: Uncaught (in promise): ReferenceError: localStorage is not defined
ReferenceError: localStorage is not defined

the service that uses it is:

import { Injectable, Inject } from '@angular/core';
import { Http, Response, Headers, RequestOptions } from '@angular/http';

import { UserRegistration } from '../shared/models/user.registration.interface';
import { ConfigService } from '../shared/utils/config.service';

import { BaseService } from "./base.service";

import { Observable } from 'rxjs/Rx';
import { BehaviorSubject } from 'rxjs/Rx';

//import * as _ from 'lodash';

// Add the RxJS Observable operators we need in this app.
import '../rxjs-operators';

@Injectable()
export class UserService extends BaseService {

  baseUrl: string = '';

  // Observable navItem source
  private _authNavStatusSource = new BehaviorSubject<boolean>(false);
  // Observable navItem stream
  authNavStatus$ = this._authNavStatusSource.asObservable();

  private loggedIn = false;

  constructor(private http: Http, private configService: ConfigService) {
    super();
    this.loggedIn = !!localStorage.getItem('auth_token');
    // ?? not sure if this the best way to broadcast the status but seems to resolve issue on page refresh where auth status is lost in
    // header component resulting in authed user nav links disappearing despite the fact user is still logged in
    this._authNavStatusSource.next(this.loggedIn);
    this.baseUrl = configService.getApiURI();
  }

    register(email: string, password: string, firstName: string, lastName: string,location: string): Observable<UserRegistration> {
    let body = JSON.stringify({ email, password, firstName, lastName,location });
    let headers = new Headers({ 'Content-Type': 'application/json' });
    let options = new RequestOptions({ headers: headers });

    return this.http.post(this.baseUrl + "/accounts", body, options)
      .map(res => true)
      .catch(this.handleError);
  }  

   login(userName: any, password: any) {
    let headers = new Headers();
    headers.append('Content-Type', 'application/json');

    return this.http
      .post(
      this.baseUrl + '/login',
      JSON.stringify({ userName, password }),{ headers }
      )
      .map(res => res.json())
      .map(res => {
        localStorage.setItem('auth_token', res.auth_token);
        this.loggedIn = true;
        this._authNavStatusSource.next(true);
        return true;
      })
      .catch(this.handleError);
  }

  logout() {
    localStorage.removeItem('auth_token');
    this.loggedIn = false;
    this._authNavStatusSource.next(false);
  }

  isLoggedIn() {
    return this.loggedIn;
  }  
}

the register ts is:

import { Component, OnInit, Inject } from '@angular/core';
import { Router } from '@angular/router';

import { UserRegistration } from '../../shared/models/user.registration.interface';
import { UserService } from "../../services/user.service";

declare var localStorage: any;

@Component({
  selector: 'app-registration-form',
  templateUrl: './registration-form.component.html'
})
export class RegistrationFormComponent implements OnInit {

 errors: string;  
 isRequesting: boolean;
 submitted: boolean = false;

 constructor(private userService: UserService, private router: Router) { 

 }

  ngOnInit() {

  }

  registerUser({ value, valid }: { value: UserRegistration, valid: boolean }) {
     this.submitted = true;
     this.isRequesting = true;
     this.errors='';
     if(valid)
     {
         this.userService.register(value.email,value.password,value.firstName,value.lastName,value.location)
                   .finally(() => this.isRequesting = false)
                   .subscribe(
                     result  => {if(result){
                         this.router.navigate(['/login'],{queryParams: {brandNew: true,email:value.email}});                         
                     }},
                     errors =>  this.errors = errors);
     }      
  }  
}

the login is:

import { Subscription } from 'rxjs';
import { Component, OnInit,OnDestroy } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';

import { Credentials } from '../../shared/models/credentials.interface';
import { UserService } from '../../services/user.service';

@Component({
  selector: 'app-login-form',
  templateUrl: './login-form.component.html'
})
export class LoginFormComponent implements OnInit, OnDestroy {

  private subscription: Subscription;

  brandNew: boolean;
  errors: string;
  isRequesting: boolean;
  submitted: boolean = false;
  credentials: Credentials = { email: '', password: '' };

  constructor(private userService: UserService, private router: Router,private activatedRoute: ActivatedRoute) { }

    ngOnInit() {

    // subscribe to router event
    this.subscription = this.activatedRoute.queryParams.subscribe(
      (param: any) => {
         this.brandNew = param['brandNew'];   
         this.credentials.email = param['email'];         
      });      
  }

   ngOnDestroy() {
    // prevent memory leak by unsubscribing
    this.subscription.unsubscribe();
  }

  login({ value, valid }: { value: Credentials, valid: boolean }) {
    this.submitted = true;
    this.isRequesting = true;
    this.errors='';
    if (valid) {
      this.userService.login(value.email, value.password)
        .finally(() => this.isRequesting = false)
        .subscribe(
        result => {         
          if (result) {
             this.router.navigate(['/home']);             
          }
        },
        error => this.errors = error);
    }
  }
}

I tried the solution from:

localStorage is not defined (Angular Universal)

but it does not work...

What am I missing

Answer 1

You can use standard API for localstorage, like

localStorage.setItem(key, val)

and

localStorage.getItem(key)

but If you want a angular solution for this and find a good library for localstorage, one I'm using is this

https://github.com/marcj/angular2-localstorage

also

https://www.npmjs.com/package/angular2-cool-storage

is cool to use.

Answer 2

The standard localStorage API should be available.

No need to declare it.

to set localStorage.setItem('name', 'storingSomething');

to get localStorage.getItem('name');