typescript playground

main.ts

export {};
let message = 'Welcome back!';
console.log(message);

// Variable Declaration
let x = 10;
const y = 20;

let sum;
const title = 'Codevolution';

// Basic Variable Types
let isBeginner: boolean = true;
let total: number = 0;
let name: string = 'Vishwas';

let sentence: string = `My name is ${name}
I am a beginner in TypeScript`;

console.log(sentence);

// Sub types
let n: null = null;
let u: undefined = undefined;

let isNew: boolean = null;
let myName: string = undefined;

// Array type

let list1: number[] = [1, 2, 3];
let list2: Array<number> = [1, 2, 3];


// Tuple type

let person1: [string, number] = ['Chris', 22];

// Enum type
enum Color {Red, Green, Blue}
let c: Color = Color.Green;
console.log(c);

// Any type
let randomValue: any = 10;
randomValue = true;
randomValue = 'Vishwas';

// Unknown type
let myVariable: any = 10;
console.log(myVariable.name.firstName);
myVariable();
myVariable.toUpperCase();

// Type inference
let a;
a = 10;
a = true;

let b = 10;

// Union Types
let multiType: number | boolean;
multiType = 20;
multiType = true;

let anyType: any;
anyType = 20;
anyType = true;

// Functions

function add(num1: number, num2: number = 10): number {
  if (num2)
    return num1 + num2;
  else
    return num1;
}

add(5, 10);
add(5);

// Interfaces

interface Person {
  firstName: string;
  lastName?: string;
}

function fullName(person: Person) {
  console.log(person.firstName + ' ' + person.lastName);
}

let p = {
  firstName: 'Bruce'
};
fullName(p);

// Classes

class Employee {
  employeeName: string;

  constructor(name: string) {
    this.employeeName = name;
  }

  greet() {
    console.log('Good morning ' + this.employeeName);
  }
}

let emp1 = new Employee('Vishwas');
console.log(emp1.employeeName);
emp1.greet();

class Manager extends Employee{
  constructor(managerName: string) {
    super(managerName);
  }
  delegateWork() {
    console.log('Manager delgating tasks' + this.employeeName);
  }
}

let m1 = new Manager('Bruce');
m1.delegateWork();
m1.greet();
console.log(m1.employeeName);

// Access Modifier

class Employee {
  public employeeName: string;
  // private employeeName: string; // when private, cannot access even from the derived class
  // protected employeeName: string; // can be accessed from derived class
  
  constructor(name: string) {
    this.employeeName = name;
  }

  greet() {
    console.log('Good morning ' + this.employeeName);
  }
}