My code is saying that number 1 is prime. How to fix that?

So,

I’m starting to learn how to code and now I have only one problem.
My code is functioning very well, until he says that the numbers 1 and 0 are prime.

I already tried to add them to exception, change the calculation and still printing that is prime.

Here’s the code:

function testPrimeNumber(num)
{
    Number(num)
    for (var i = 2; i < num; i++)
    {
        if (num % i == 0)                
        {
            return ("The number "+num+" isn't prime.");                
        }                                
        else {}                
    }      
    return ("The number "+num+" is prime.");   
} 

console.log("result for 1:", testPrimeNumber(1));

What am I doing wrong here?

>Solution :

You should test for 0 and 1 at the start of the function. At the moment your code is skipping the for loop (because 1 < 2 and 0 < 2) and going straight to saying the number is prime.