What is the Javascript "Return" function for?

Question

One of the functions I hate the most is the "Return" because I don’t understand what she does or didn’t do:

var quarter = function(number){
number / 4;
}


if (quarter(12) % 3 === 0 ) {
console.log("A declaração é verdadeira");
} else {
console.log("A declaração é falsa");
}

Well, if they execute this code in Java it occurs that "The Statement is false" 12 being divided by 4 of the quotient 3, is 3 dividing by 3, of the rest 0, which should give "The statement is true" but for a OBSCURE reason gives "The Statement is false". Now we’ll do another test:

var quarter = function(number){
 return number / 4;
}


if (quarter(12) % 3 === 0 ) {
console.log("A declaração é verdadeira");
} else {
console.log("A declaração é falsa");
}

If the attentive ones are the ones who will not notice, I put the "Return" before the variable "number", but for ANOTHER OBSCURE REASON , this example, if executed on your computer will give "The Declaration is true"! where in the first example it only gave "The Declaration is false!" as only a function changes something that should or should not happen. I want you to explain how the Return variable works what it does, what it fails to do, ALL its functions are its working examples. Besides telling me why example 1 is 2 are different. I appreciate it if you read it. but I really need your help help PLEASE! I hope to talk in the chat bye <3

Answer 1

The return is not a function but an instruction (or command/functionality) of functions in many programming languages. What the return is to return a value that is the product of the function, and with this interrupts the rest of the function processing.

Among the reasons we use functions are chunks of complex logic or need to reuse the same code with different input data. Now the way the function returns what we want from these pieces of code (functions) is by using return.

When a function ends without having called a return the value it leaves or returns is undefined.

Take a look at these examples:

function foo(){
   // sem nada
}

function bar(){
    return 10;
}

console.log(foo()); // dá undefined
console.log(bar()); // dá 10

The difference, as in your example, is that Return returns the result of the function. And this result can be saved in a variable! Look at this example:

var a = bar();
console.log(a); // 10

gives 10 because the function return value has now been saved in the variable.

In your first example when you have at the end of the function only number / 4;, without the return, interpreter runs that command, or seka calculates the fourth part of number but does not pass this value back to the one who called the function. For that you need to return number / 4;