Explain the following javascript statement? -

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var ninja = (function(){     function ninja(){}     return new ninja(); })(); 

i've been learning javascript while now. why function declaration above encapsulated in '('s , why there '();' in end?

i can imagine constructor function, because of '();' in end. why object wrapped in simple brackets?

this code equivalent to:

function ninja() {     // nothing here }  var ninja = new ninja(); 

though in code listed, function/object ninja not global scope.

the code (function() {...})(); says "take whatever function contained inside here , execute immediately". it's creating anonymous function , calling right afterwards.