Node.js JavaScript syntax

I see a piece of JavaScript code in my Node.js application.

( function() { console.log("gg") } )(this)

I would like to know why use => ( function(){} )(this) this type of structure, and how does this compile.

I am understanding why we have this two brackets ()(), and why this code would work.

Answer

This is a self invoking anonymous function. This pattern is useful when you want to hide variables from the global namespace.

(function(){
    var foo = "foo";
})();

console.log(window.foo); // undefined

Also see What do parentheses surrounding a JavaScript object/function/class declaration mean?

What advantages does using (function(window, document, undefined) { … })(window, document) confer?