Why is my JavaScript function not returning the expected value?

Question

I was trying to write a simple JavaScript function that calculates the square of a number. But instead of returning the correct result, it gives me undefined. Here is my code:

function square(num) {
let result = num * num;
console.log(result);
}
let output = square(5);
console.log(output);

The console prints 25 inside the function, but when I log output, it shows undefined.

Can anyone explain why this is happening and how to fix it so the function actually returns the result?

Answer 1

In your function you used console.log(result) but didn’t return it.
If a JavaScript function doesn’t return anything, it gives undefined by default.

That’s why when you do let output = square(5);, the value of output becomes undefined.

To fix this, replace console.log(result); with return result;.

✅ Correct code:

function square(num) {
let result = num * num;
return result; // now it will return 25
}

let output = square(5);
console.log(output); // 25

So basically, console.log() only shows the value in the console, but to actually send the value outside the function you need return.

Answer 2

Xrantu your code should be
console.log(result);
As a
return result;

function square(num) {
let result = num * num;
return result; // return 25
}
let output = square(5);
console.log(output);

Otherwise the second output is undefined
As:
console.log(output): //undefined in your code

Answer 3

Yes