1. IIFE – Javascript
Immediately-invoked function
expression
A summary by Suresh Koya

2. Why Iffy matters?
l To avoid variable hoisting from within blocks,
protect against polluting the global environment
and simultaneously allow public access to
methods while retaining privacy for variables
defined within the function.
Additional information @https://en.wikipedia.org/wiki/Immediately-invoked_function_expression

3. Basic Example
(function() {
// the code here is executed once in its own scope
}());

4. Usage - 1
(function( global, factory ) {
// code here
} (typeof window !== "undefined" ? window : this, function( window,
noGlobal ) {
//more code here
}));
- jQuery library code

5. Usage- 2
!function() {
// More code here
}();
- d3 library code

6. Usage - 3
+function ($) {
// Some code here
}(jQuery);
- bootstrap library code

7. Usage - 4
;(function() {
//Code here
}.call(this));
- Lodash library code

8. Summary
lWell these are just syntactic sugars. The reason
to use is to avoid variable conflicts and use
namespacing
lDetailed discussion
@http://stackoverflow.com/questions/3755606/what-
does-the-exclamation-mark-do-before-the-function