We might have some extra code for defining types but in the end, it's only for the better.

employee.ts

// Employee class is bascially a blueprint of any employee object that can be instantiated with this piece of code.
class Employee {
    public employeeName: string; // A public variable of type STRING
    private salary: number; // A private variable of type NUMBER

    constructor(employeeName: string, salary: number) {
        this.employeeName = employeeName;
        this.salary = salary;
    } // A contructor to create an employee object with a predefined salary and name.

    public promotion(): void {
        this.salary += 1000;
    } // Adding 1000 to the emplyee's current salary.

    public printSalary():void {
        console.log(this.employeeName + '\'s salary is: ' +  this.salary);
    } // This method prints the employee name and his/her salary. 
}
// Instantiate (create) an object from a class
let employee = new Employee('Bob', 1000);

employee.printSalary();
employee.promotion();
employee.printSalary();

// Result =>
// Bob's salary is: 1000 
// Bob's salary is: 2000