Functions.ts

// Regular Functions

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

console.log(add(5, 3)); // Output: 8

// Function Expressions
const multiply = function (a: number, b: number): number {
  return a * b;
};

console.log(multiply(4, 5)); // Output: 20

// Arrow Functions
const subtract = (a: number, b: number): number => {
  return a - b;
};

console.log(subtract(10, 4)); // Output: 6

// Optional Parameters
function greet(name: string, greeting?: string): string {
  return greeting ? `${greeting}, ${name}!` : `Hello, ${name}!`;
}

console.log(greet("Alice")); // Output: Hello, Alice!
console.log(greet("Alice", "Hi")); // Output: Hi, Alice!

// Default Parameters

function power(base: number, exponent: number = 2): number {
  return base ** exponent;
}

console.log(power(3)); // Output: 9
console.log(power(3, 3)); // Output: 27

//  Rest Parameters

function sum(...numbers: number[]): number {
  return numbers.reduce((total, num) => total + num, 0);
}

console.log(sum(1, 2, 3)); // Output: 6
console.log(sum(4, 5, 6, 7)); // Output: 22

// Function Overloading

function display(value: string): void;
function display(value: number): void;
function display(value: string | number): void {
  console.log(`Value: ${value}`);
}

display("Hello"); // Output: Value: Hello
display(42); // Output: Value: 42

// Function Types
type Operation = (a: number, b: number) => number;

// const add: Operation = (a, b) => a + b;
// const multiply: Operation = (a, b) => a * b;

// console.log(add(5, 3)); // Output: 8
// console.log(multiply(4, 5)); // Output: 20

// Callback Functions

function fetchData(url: string, callback: (data: string) => void): void {
  // Simulate fetching data
  const data = "Sample data from " + url;
  callback(data);
}

fetchData("https://api.example.com", (data) => {
  console.log(data); // Output: Sample data from https://api.example.com
});

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

// console.log(identity<string>("Hello")); // Output: Hello
// console.log(identity<number>(42)); // Output: 42