PranavBhatia

// Generics are types which can hold/use several types

let employeeNamesArray: Array<string>; // This array will only accept strings

// employeeNamesArray = [123]; // => Error
employeeNamesArray = ['Bob', 'Sam'];

console.log(employeeNamesArray); // Result => [ 'Bob', 'Sam' ]

PranavBhatia

// Interface can also be called a contract.
// We can use them to define custom types without creating classes.
// Interfaces ARE NOT compiled to JavaScript! It's just for checking/validation done by our TypeScript compiler.

// Employee interface
interface Employee {
    employeeName: string;
    salary: number;
    mobileNumber?: string; // Optional property => Does not have to be implemented
}

PranavBhatia

// 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.