JavaScript – How to modify 'variable' inside function so that it does not revert to original value after function termination?

I have a script like this:

function changeValue(x){
    x = 30;
}

let a = 3;
changeValue(a);
console.log(a);

The above code outputs 3, but the expected output is 30.
Now I’m aware why this is happening, but how do I modify my code so that the changes made do not revert after the changeValue function ends?
I have read that there are no explicit pointers in JS and I don’t want to alter the value using the global variable name or by using the object approach. Is there any other way to solve the problem?

Thank you

>Solution :

The best way would be to use return, because x isn’t an object, it’s just a variable. It is discarded after the function.

Using Return:

function changeValue(x){
    return 30;
}

let a = changeValue(3);
changeValue(a);
console.log("Output Is:", a);