This is similar syntax to this:
(function() {
}());
which is called an immediate function. the function is defined and executed immediately. the pros to this is that you can place all of your code inside this block, and assign the function to a single global variable, thus reducing global namespace pollution. it provides a nice contained scope within the function.
This is the typical pattern i use when writing a module:
var MY_MODULE = (function() {
//local variables
var variable1,
variable2,
_self = {},
etc
// public API
_self = {
someMethod: function () {
}
}
return _self;
}());
not sure what the cons might be exactly, if someone else knows of any i would be happy to learn about them.
