Parentheses in IIFE in JavaScript

Normally, parentheses are used instead of plus when calling a function in-place, because this style is considered more obvious:

(function() {
	console.log('!');
}());

Most often, the parentheses of a function call are placed outside, like this:

(function() {
	console.log('!');
})();

Determine what will be output to the console without running the code:

let result = (function() {
	return '!';
}());

console.log(result);

Determine what will be output to the console without running the code:

let result = (function() {
	return '!';
})();

console.log(result);

Determine what will be output to the console without running the code:

let result = (function() {
	return '!';
});

console.log(result);

Determine what will be output to the console without running the code:

let result = (function() {
	return '!';
});

console.log(result());