Meta programming in TypeScript

main.ts

class User {
  name: string;
  age: number;

  #createdAt: Date;

  constructor(name: string, age: number) {
    this.name = name;
    this.age = age;

    this.#createdAt = new Date();
  }

  get profile(): string {
    return `Name: ${this.name}, Age: ${this.age} (created: ${this.#createdAt})`;
  }

  hello(): string {
    return `${this.#helloPrefix()}, I'm ${this.name}!`;
  }

  #helloPrefix(): string {
    return "Hi";
  }
}

class AdminUser extends User {}

const log = console.log;

(function main() {
  const user = new User("bob", 20);

  // Get a class from an instance
  log(user.constructor === User);
  //=> true

  // Get a class name as string
  // @returns {string}
  log(User.name);
  //=> "User"

  // Get public methods
  // @returns {string[]}
  log(Object.getOwnPropertyNames(User.prototype));
  //=> ["constructor", "profile", "hello"]

  // Get public properties
  // @returns {string[]}
  log(Object.getOwnPropertyNames(user));
  //=> ["name", "age"]

  // Get an ancestor
  // I'm not sure this is correct in any cases.
  log(Object.getPrototypeOf(AdminUser) === User);
  //=> true
})();