? JavaScript Functions

Functions are reusable blocks of code designed to perform a task.

1. Function Declaration

function greet(name) {  return `Hello, ${name}!`;}console.log(greet("Alice")); // Hello, Alice!

2. Function Expression

const greet = function(name) {  return `Hello, ${name}!`;};console.log(greet("Bob"));

3. Arrow Functions (ES6+)

const greet = (name) => `Hello, ${name}!`;console.log(greet("Carol"));

4. Parameters and Arguments

function add(a, b = 0) {  return a + b;}console.log(add(5));     // 5 (b defaults to 0)console.log(add(5, 3));  // 8

5. Returning Values

function square(x) {  return x * x;}

6. Anonymous Functions

Functions without names, often used as callbacks:

setTimeout(function() {  console.log("Hello after 1 second");}, 1000);

7. Immediately Invoked Function Expression (IIFE)

(function() {  console.log("This runs immediately!");})();

8. Rest Parameters and Default Parameters

function sum(...numbers) {  return numbers.reduce((a, b) => a + b, 0);}console.log(sum(1, 2, 3, 4)); // 10

Want examples of closures, callback functions, or function scopes?