Angular and Firebase Authentification: problem with understanding json.parse example

I am trying to use a tutorial to make my first authentication setup with firebase in angular.

I do not understand the practice of instantly getting the user-item from the local storage after stringifying it.

/* Saving user data in localstorage when 
    logged in and setting up null when logged out */
    this.afAuth.authState.subscribe((user) => {
      if (user) {
        this.userData = user;
        localStorage.setItem('user', JSON.stringify(this.userData));
        JSON.parse(localStorage.getItem('user')!);
      } else {
        localStorage.setItem('user', 'null');
        JSON.parse(localStorage.getItem('user')!);
      }
    });
  }

What could be the purpose if the JSON is not being stored in a variable?

https://www.positronx.io/full-angular-firebase-authentication-system/

https://github.com/SinghDigamber/angularfirebase-authentication/blob/master/src/app/shared/services/auth.service.ts

I could not contact the author so I have to ask here.