In JavaScript, a mutable variable is one whose value can be changed after it has been initially set. This is in contrast to immutable variables,
whose values cannot be changed once they are set.
Exporting mutable variables can lead to unpredictable behavior and bugs in your code. This is because any module that imports the variable can
change its value. If multiple modules import and change the value of the same variable, it can become difficult to track what the current value of the
variable is and which module changed it last.
