Node.js JavaScript syntax [duplicate]

Question

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.

Ok, the interesting thing is though, why (this) is passed?!? — loveNoHate
– loveNoHate, Commented Mar 7, 2014 at 18:35

Community · Accepted Answer · 2017-05-23 12:02:13Z

22

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

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answered Mar 7, 2014 at 18:30

webpapaya

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3 Comments

How about (function(){})(this); Does "this" invoke this function? How about (function(global, requirejs, require){})(this, requirejs, require) ?

these are just additional parameters which you can pass to the given function I'll fix this in my answer

i think this explains everything you need to know link