Singelton typescript

singelton.ts

class AuthService {
  private static instance: AuthService;
  private _counter: number = 0;
  constructor() {
    console.log('AuthService constructor')
  }
  public static getInstance() {
    console.log('AuthService getInstance')
    if (!AuthService.instance) {
      AuthService.instance = new AuthService();
    }
    return AuthService.instance;
  }

  set counter(num: number) {
    this._counter = num;
  }

  get counter() {
    return this._counter;
  }

  public increateCounter() {
    this.counter = this.counter + 1;
  }

  public showCounter() {
    return 'Counter: ' + this.counter;
  }
}

export default AuthService.getInstance();