Question

How to invoke an IIFE without any extra brackets?

Answer 1

Immediately Invoked Function Expressions(IIFE) requires a pair of parenthesis to wrap the function which contains set of statements.

(function (dt) {
  console.log(dt.toLocaleTimeString());
})(new Date());

Since both IIFE and void operator discard the result of an expression, you can avoid the extra brackets using void operator for IIFE as below,

void (function (dt) {
  console.log(dt.toLocaleTimeString());
})(new Date());