feat: add contants rule

Author: ExploitEngineer

part1 (Basics)/01_variables.js

@@ -1,36 +1,30 @@
-// variables.js
-
 // Using let (recommended for variables that can change)
-let age = 20;  // Declare and initialize variable
-age = 30;      // Update the value
-
+let age = 20; // Declare and initialize variable
+age = 30; // Update the value
 
 // Using const (for constant values that should not change)
-const pi = 3.14;  // Declare and initialize constant
-
+// NOTE: It's better to use all letters upppercase when using constants
+const PI = 3.14; // Declare and initialize constant
 
 // Using var (old way, avoid if possible)
 // var declarations are function-scoped and can lead to unexpected behavior
 var name = "John";
 
-
 // Variable scope examples:
 
 // Block scope with let and const
 if (true) {
   let blockScoped = "I exist only inside this block";
   const constantScoped = "Also block-scoped";
-  console.log(blockScoped);    // Works here
+  console.log(blockScoped); // Works here
 }
 // console.log(blockScoped);   // Error: blockScoped is not defined
 
-
 // var is function scoped, not block scoped
 if (true) {
   var functionScoped = "I exist inside the function or globally";
 }
-console.log(functionScoped);  // Works here (if not inside a function)
-
+console.log(functionScoped); // Works here (if not inside a function)
 
 // Variable naming rules:
 // - Can contain letters, digits, underscores, and dollar signs
@@ -45,12 +39,9 @@ let _count;
 // Example of invalid variable name:
 // let 1stName;  // Syntax Error
 
-
 // Variables declared without let, const, or var become global (avoid this)
 function wrongExample() {
-  someVar = 10;  // Declares a global variable unintentionally
+  someVar = 10; // Declares a global variable unintentionally
 }
 wrongExample();
-console.log(someVar);  // 10 (global scope)
-
-
+console.log(someVar); // 10 (global scope)