In this session we will create the Immediately Invoked Function Expression. IIFE’s are very useful for executing one time code/script. It also guards us from accidentally creating global variables. NOTE: IIFE’s are also know as Self Executing Anonymous Function.
Step 1: IIFE
(function (window, undefined) {
alert(window);
}(window));
Here, we are passing the global window object as a parameter to the IIFE. This allows a global object to be made available as a local parameter, which kind of improves the performance slightly as method lookup is avoided.
We are also passing “undefined” to create a true undefined without being worried about other libraries overwriting it. (Note this may not be needed as modern JavaScript prevents this, but still a good practice).
When you save the library code and execute the function you should get an alert.