feat: add hoisting.js

Author: ExploitEngineer

part1 (Basics)/13_hoisting.js

@@ -1,14 +1,43 @@
-getName();
-// JavaScript
+// hoisting.js
 
-console.log(x);
-// undefined
+// INFO: Hoisting in JavaScript
 
+/*
+Hoisting is a JavaScript mechanism where variables and function declarations
+are moved to the top of their scope (memory phase) before code execution.
+
+Important:
+- Only **declarations** are hoisted, not **initializations**.
+- Function declarations are fully hoisted.
+- var is hoisted and initialized as undefined.
+- let and const are hoisted but not initialized (temporal dead zone).
+*/
+
+// Function call before it's defined – this works because function declarations are hoisted
+getName(); // Output: "JavaScript"
+
+// Accessing a 'var' variable before declaration – it's hoisted with undefined
+console.log(x); // Output: undefined
+
+// Accessing the function by name – shows the function definition
 console.log(getName);
-// function getName() {}
+// Output: [Function: getName]
 
 var x = 7;
 
+// Function Declaration
 function getName() {
   console.log("JavaScript");
 }
+
+/*
+Summary:
+
+- Function declarations are hoisted completely (both name and body).
+- var is hoisted and set to undefined.
+- let and const are hoisted but in the "temporal dead zone" – accessing them before declaration causes ReferenceError.
+
+Good Practice:
+- Always declare variables and functions at the top of their scope.
+- Prefer let and const over var to avoid confusion caused by hoisting.
+*/