Typescript TS2339 Property doesn't exist on type - Class decleration

Question

I am using exact example outlined in Typescript https://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes.html#classes

This is exact copy I am running in app

Answer 1

This seems to work fine?

var Student = (function() {
  function Student(firstName, middleInitial, lastName) {
    this.firstName = firstName;
    this.middleInitial = middleInitial;
    this.lastName = lastName;
    this.fullName = firstName + " " + middleInitial + " " + lastName;
  }
  return Student;
}());

function greeter(person) {
  return "Hello, " + person.firstName + " " + person.lastName;
}
var user = new Student("Jane", "M.", "User");
document.body.innerHTML = greeter(user);