It's a code smell, really.
You know what's even worse? Dependency Hell is like the in-laws who just won't leave.
So, here's a little code to help you out:
const globalVariable = 'I am the global variable!';
const functionToAvoid = () => {
console.log(globalVariable);
};
// Don't do this.
Instead, use Dependency Injection and keep your code sane.