Advanced Functions

Declaration vs. Expression (Arrow)

There are two main ways to write functions:

// Traditional function (Old syntax)
function sumar(a, b) {
    return a + b;
}

// Arrow Function (Modern syntax - ES6)
const sumar = (a, b) => a + b;

Advantages of Arrow Functions:

• Shorter and cleaner syntax.
• Implicit return if it’s a single line.
• They don’t create their own this context (they inherit it from the parent).

Higher-Order Functions

These are functions that can receive other functions as arguments or return them. This enables much more modular code.

setTimeout()

Executes a function after a specified time (in milliseconds).

setTimeout(() => {
    console.log("1 second passed");
}, 1000);

Map, Filter and Reduce

As we saw in the Arrays section, these methods are the heart of functional programming in JavaScript because they operate using other functions (callbacks).