tf-23.ts

class User {
  username: string;
  age: number;

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

  [propName: string]: string | number;
}


const user = new User('John', 23);
user['phone'] = '+3434234898';

const something = user['something'];