No tests do not tick, even though all requirements are met

[itsbillyy]

Challenge Factorialize a Number has an issue.
User Agent is: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36.
Please describe how to reproduce this issue, and include links to screenshots if possible.
After manually testing all the requirements, the tests do not tick.

My code:

var numberValue = 1;
function factorialize(num) {
  for (i=1; i<= num; i++) {
    numberValue *= i;
  }
  return Number(numberValue);
}
factorialize(0);

[erictleung]

@itsbillyy our tests run your function factorialize() sequentially, one after each other. So global variables are changed with each run. Move your numberValue global variable within your function and you should pass the challenge. Happy coding!

[JohnnyBizzel]

I'm not sure you should close this issue. It is clearly valid to have global variables.

[erictleung]

@JohnnyBizzel yes, global variables are perfectly valid to use in code. Nonetheless, this is a duplicate of #9199 and this would've been closed in favor of that one. Feel free to continue the discussion over in the other issue. Happy coding!