feat: update datatypes

added proper datatypes with proper explanation & checked each datatype
type using typeof property

Author: ExploitEngineer

part1 (Basics)/02_datatypes.js

@@ -1,6 +1,5 @@
-// datatypes.js
-
 /*
+INFO: DataTypes
 JavaScript is dynamically typed, so variables can hold any type of data without explicit type declaration.
 
 Common data types in JavaScript:
@@ -19,7 +18,7 @@ Common data types in JavaScript:
 
 // String
 let name = "whoami";
-console.log(name); // whoami
+console.log(name); // "whoami"
 
 // Number
 let score = 102;
@@ -29,22 +28,40 @@ console.log(score); // 102
 let isLoggedIn = false;
 console.log(isLoggedIn); // false
 
-// Object - Array
+// BigInt (used for very large integers beyond Number limit)
+let largeNumber = 1234567890123456789012345678901234567890n;
+console.log(largeNumber); // 1234567890123456789012345678901234567890n
+
+// Undefined (a variable declared but not assigned a value)
+let something;
+console.log(something); // undefined
+
+// Null (represents an intentional empty value)
+let emptyValue = null;
+console.log(emptyValue); // null
+
+// Object – Array
 let teaTypes = ["lemon tea", "orange tea", "oolong tea"];
 console.log(teaTypes); // ["lemon tea", "orange tea", "oolong tea"]
 
-// Object - Plain Object
-let user = { firstName: "whoami", lastName: "dsnake0" };
+// Object – Plain Object
+let user = {
+  firstName: "whoami",
+  lastName: "dsnake0",
+};
 console.log(user); // { firstName: "whoami", lastName: "dsnake0" }
 
-// Assigning variable values
-let getScore = score;
-console.log(getScore); // 102
+// Symbol (used to create unique identifiers)
+let uniqueId = Symbol("id");
+console.log(uniqueId); // Symbol(id)
 
-// Undefined example
-let something;
-console.log(something); // undefined
+// INFO: Type of each DataTypes
 
-// Null example
-let emptyValue = null;
-console.log(emptyValue); // null
+console.log(typeof name); // "string"
+console.log(typeof score); // "number"
+console.log(typeof isLoggedIn); // "boolean"
+console.log(typeof largeNumber); // "bigint"
+console.log(typeof something); // "undefined"
+console.log(typeof emptyValue); // "object" (this is a historical JS bug)
+console.log(typeof teaTypes); // "object"
+console.log(typeof uniqueId); // "symbol"