الدوال والأنواع العامة

function add(a: number, b: number): number {
  return a + b;
}

const result = add(5, 3); // 8

function greet(name: string, greeting: string = 'Hello'): string {
  return `${greeting}, ${name}!`;
}

greet('Ahmed');           // 'Hello, Ahmed!'
greet('Salaam', 'Salaam'); // 'Salaam, Salaam!'

const multiply = (a: number, b: number): number => a * b;

const double = (x: number): number => x * 2;

function format(value: string): string;
function format(value: number): string;
function format(value: string | number): string {
  if (typeof value === 'string') return value;
  return value.toFixed(2);
}

function identity<T>(arg: T): T {
  return arg;
}

const num = identity<number>(42);    // 42
const str = identity<string>('hello'); // 'hello'

function process(value: string | number) {
  if (typeof value === 'string') {
    return value.toUpperCase();
  }
  return value.toFixed(2);
}