Required module does not update when the variable inside that module changes

I have a javascript file and in it I require another file that has a variable that changes.

main.js

let num = require("./extra").num

extra.js

let num = 5;

setInterval(() => {
  if (num > 0) {
    num--;
  }
  console.log(num);
}, 1000);

module.exports = {
  num
};

Now in the main.js file that variable num is always 5 and never changes. What do I need to do to get it updated all the time?

Note: I'm declaring the variable in main.js AFTER the variable changes so it shouldnt't be 5

from Required module does not update when the variable inside that module changes