Change original variable value by changing value of passed function parameter

Question

Is it possible to change the variable value with function like example below? Whenever I change the passed parameter value the original value doesn't change. Why is this happening?

let b = 3;
function t(n) {
    n = 5; 
}

t(b)
console.log(b) // still 3

I know this can be done like this, but I am wondering why the example above wont work.

let b = 3;

function t() {
    return 5;
}

b = t();
console.log(b)

Answer 1

Passing scalar values to function will pass them by value, not by reference.

One solution would be to pass it as object:

 let b = {value: 3}; function t(n) { n.value = 5; } t(b); console.log(b.value);