JS Functions

function nameofFuction(parameter1, parameter2) {
    //code to execute
}


//example
function saludar(nombre) {
    console.log("Hola, " + nombre + "!");
}


//******"****
//1. CALLING A FUNCTION
function saludar(nombre) {
console.log("Hola, " + nombre + "!");
}
//Calls the function with "Juan" as an argument
saludar("Juan");

//************
//2. PARAMETERS AND ARGUMENTS 
function addition(a, b) {
    let resultado = a + b;
    console.log("The addition is: " + resultado);
}

addition(5, 10); //The addition is: 15


//**************
//3. RETURN A VALUE
function multiply(a, b) {
    return a * b;
}

let total = multiply(4, 5);
console.log("The total is: " + total); // The total is: 20

//**************
//4. ANONYMOUS FUNCTIONS
//Nameless functions that can be assigned to variables
let greet = function(name) {
   return "Hi, " + name + "!";
};

console.log(greet("Ana")); //Hi, Ana!


//*************
//5. ARROW FUNCTIONS
//A shorter syntax to define anonymous functions
let nameOfFunction = (parameter1, parameter2) => {
    //code to execute
};

//***************
// 6.FUNCTIONS AS FIRST CLASS OBJECTS
function operationMath(operation, a, b) {
    return operation(a, b);
}

let sum = (x, y) => x + y;
let product = (x, y) => x * y;

console.log(operationMath(sum, 5, 3));
console.log(operationMath(product, 5, 3));


//*****************
//7. Superior Order Functions
//Functions which can receive other functions as arguments and return functions as results. 
//This is possible since functions in Javascript are first class objects.

function applyOperation(operation, a, b) {
    return operation(a, b);
}

function sum(x, y) {
    return x + y;
}

function product(x, y) {
    return x * y;
}

console.log(applyOperation(sum, 10, 20));
console.log(applyOperation(product, 10, 20));

//****************
//8. CLOSURES
//A function which remembers the lexical environment, the variables that were in the scope when the function was defined. 
//This allows functions to access variables of its outside scope even after the context that they were created in was over.

function createCount() {
    let counter = 0;
    return function() {
        counter++;
        return counter;
    };
}

let counter1 = createCount();
console.log(counter1());
console.log(counter1());

let counter2 = createCount();
console.log(counter2());

//************
//9. RECURSIVITY

function factorial(n) {
    if (n === 0) {
        return 1;
    } else {
        return n * factorial(n - 1);
    }
}

console.log(factorial(5));