The void operator evaluates its argument and unconditionally returns undefined. It can be useful in pre-ECMAScript 5
environments, where undefined could be reassigned, but generally, its use makes code harder to understand.
void doSomething();
doSomething();
No issue is raised when void 0 is used in place of undefined.
if (parameter === void 0) {...}
No issue is also raised when void is used before immediately invoked function expressions.
void (function() {
...
}());