what is difference to use or not to use parenths before function in javascript

Question

What is difference between following code?

Code 1:

var f = function() {

  // function body code
  // ...
  // ...

}();

Code 2:

var f = (function(){

  // function body code
  // ...
  // ...

})();

Which one is better to use?

Answer 1

They're exactly equivalent given the syntax of the language.

Answer 2

They are equivalent. The second one might be more clear, though.

Answer 3

Since it would be invalid syntax without the assignment, as in

function() {
    // ...
}();

it may be clearer to always wrap anonymous functions in parentheses.