So far, we have only worked with interfaces to represent data, and we still want to continue using interfaces when passing data around various components and services. However, there's a need to create a default object to initialize a BehaviorSubject. In Object-oriented Programming (OOP), it makes a lot of sense for the User object to own this functionality instead of a service. So, let's implement a User class to achieve this goal.

Inside the user/user folder, define an IUser interface and a User class provided in UserModule:

src/app/user/user/user.ts
import { Role } from '../../auth/role.enum'

export interface IUser {
  id: string
  email: string
  name: {
    first: string
    middle: string
    last: string
  }
  picture: string
  role: Role
  userStatus: boolean
  dateOfBirth: Date
  address: {
    line1: string
    line2: string...