Advanced Functions

Declaration vs. Expression (Arrow)

There are two main ways to write functions:

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

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

Advantages of Arrow Functions:

• Shorter and cleaner syntax.
• The return is implicit 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 allows much more modular code.

setTimeout()

Executes a function after a determined 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 since they operate using other functions (callbacks).