JavaScript Functions

Function Declaration

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

Function Expression

const greet = function(name) {
    return `Hello, ${name}!`;
};

Arrow Functions (ES6+)

// Full syntax
const greet = (name) => {
    return `Hello, ${name}!`;
};

// Short syntax (single expression)
const greet = name => `Hello, ${name}!`;

// No parameters
const sayHi = () => "Hi!";

Default Parameters

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

Rest Parameters

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