The void operator evaluates it's argument and unconditionally returns undefined. There are only rare justifications for
using it. The assignment of undefined is a bad practice - it should only be seen as a starting value for an uninitialized variable - and
the evaluation of the argument can be handled by other means. Further, the use of void, which can be used with or without parentheses, so
could be confusing.
void(function() {
...
}());
(function() {
...
}());