Learn Shadowing in JavaScript and IIFE- Day 4

 In this articles, we learn about  Shadowing in JavaScript and IIFE.

1.Shadowing in JavaScript:  

• In a programming language, shadowing occurs when a variable is declared in certain scope has the same name defined on its outer scope.
• In the inner scope, both variables scope overlap.
• Simply shadowing means an exact copy of anything.

• So, there are two concepts:

         1.Variable  Shadowing

         2. Function Shadowing

• Outer variable or function is shadowed by the inner variable or function.
• Inner variable or function is mask of outer variable or function.

Example:

Program:

Output:

2.IIFE:

• IIFE stands for Immediately Invoke Function Expression.
• IIFE is a way to execute functions immediately as soon as they are created.
• IIFE contains parenthesis ()which are important here, these parenthesis contain expression not a statement.
•  IIFE has a "function or variable" defined inside IIFE,can not be accessed outside the IIFE  block, thus preventing global scope from getting polluted.

Syntax:

( function () {

// function logic here.

}) ();

Example:

Program:

Output:

Thank you!!!!!!!!!!!!