Anonymous Wrappers and Namespaces

anonymouswrappers.js

(
  // evaluate the function in the parenthesis
  function(){}
  // return the evaluated function object
)() // call it immediately

// The same functionality can be done as follows;
!function(){}()
+function(){}()
(function(){}());

// PRO TIP:
// if some jerk on your team does this. AKA overwrites the global variable "undefined"

console.log(typeof undefined === "undefined") // true
var undefined = 123;
console.log(typeof undefined === "undefined") // this is false! undefined is overwritten and replaced by the number 123

// you can avoid a catastrophe by using an anonymous wrapper.

(function(undefined){console.log(undefined);})();