TypeScript, JavaScript में क्या जोड़ता है

let name: string = 'Alice';
let age: number = 30;
let active: boolean = true;

let count: number = 5;
count = 'hello'; // Error: Type 'string' is not assignable to type 'number'

interface User {
  name: string;
  age: number;
}

const alice: User = { name: 'Alice', age: 30 };

enum Direction { Up, Down, Left, Right }
const move: Direction = Direction.Up;

function identity<T>(value: T): T {
  return value;
}
const n = identity<number>(42);

class BankAccount {
  private balance: number = 0;
  deposit(amount: number) { this.balance += amount; }
}

let name: string = null; // Error with strictNullChecks
let maybeName: string | null = null; // OK