On some JS code on some sites I see Javascript code such as this:
SomeName.init = (function () {
// some stuff
})();
I mean, this is not a jQuery plugin code such as this:
(function( $ ){
$.fn.myPlugin = function() {
// Do your awesome plugin stuff here
};
})( jQuery );
Then, what is it? and what is the resulting JS object?
It's a anonymous function, which doesn't leak variables to the global scope when declaring variables using var.
SomeName.init = (function () {
return 3.1415;
})();
SomeName.init is a number (3.1415), because () after the anonymous function declaration executes the function. There's no way to obtain the original function, unless defined within the anonymous function:
(function foo(){
//foo refers to this function
too = foo;
})();;
//foo is undefined
//too refers to the function, because `too` has been defined without var
The Module Pattern. And those two snippets have more in common than you think.
(function () {
// some stuff
})()
is a anonymous function that calls itself instantly. It's just a closure around the code inside to stop the variable scope becoming global.
Whatever the function returns.
(function() {
//...
})();
Is used as a way to namespace code, or declare self-executing constructors. The resulting object is whatever that self-executing function returns.
The second snippet doesn't return anything and there is no resulting JS object.
