Le code suivant génère une erreur en TS  :

class Student {

     fullName: string;
     constructor(public firstName: string, public middleInitial: string, public lastName: string) {
         this.fullName = firstName + " " + middleInitial + " " + lastName;
     }
}
let s = new Student("Joe", "R", "Biden");
console.log(s.fullName);
console.log(s.firstName);