How can I use advanced variables in my functions?

How can I use advanced variables in my functions?

You can use advanced variables like closures, default parameters, and rest/spread syntax to enhance your functions.

Can you explain closures with an example?

Sure! A closure is a function that retains access to its lexical scope, even when the function is executed outside that scope. For example:

function outerFunction() {
    let outerVariable = 'I am from outer function';
    function innerFunction() {
        console.log(outerVariable);
    }
    return innerFunction;
}

const myInnerFunction = outerFunction();
myInnerFunction(); // Outputs: I am from outer function

What about default parameters?

Default parameters allow you to initialize named parameters with default values if no value or undefined is passed. For example:

function greet(name = 'Guest') {
    console.log(`Hello, ${name}!`);
}

greet(); // Outputs: Hello, Guest!
greet('Alice'); // Outputs: Hello, Alice!

And how do rest and spread syntax work?

Rest syntax allows you to represent an indefinite number of arguments as an array, while spread syntax allows you to expand an array into individual elements. For example:

function sum(...numbers) {
    return numbers.reduce((acc, num) => acc + num, 0);
}

console.log(sum(1, 2, 3)); // Outputs: 6

const arr = [1, 2, 3];
console.log(...arr); // Outputs: 1 2 3