🚀 JavaScript Variables and Data Types: A Complete Guide 🎯

🌟 Understanding Variables in JavaScript

A variable is a container for storing data values. In JavaScript, we use var, let, and const to declare variables.

🔹 Declaring Variables

var name = "Vivek"; // Old way (Not recommended) let age = 24; // Preferred for changing values const country = "India"; // Preferred for constant values

📌 Key Differences:

✅ var – Function-scoped, can be redeclared & updated (not recommended).
✅ let – Block-scoped, can be updated but not redeclared.
✅ const – Block-scoped, cannot be updated or redeclared.

🔥 JavaScript Data Types

JavaScript has two main categories of data types:

1️⃣ Primitive Data Types (Stored by value)

🔹 String – Represents text. let message = "Hello, JavaScript!";

🔹 Number – Represents both integers & floating points. let score = 99.5;

🔹 Boolean – Represents true or false. let isJavaScriptFun = true;

🔹 Undefined – A variable without an assigned value. let x; // x is undefined

🔹 Null – Represents an intentional absence of value. let y = null;

🔹 Symbol (ES6) – Unique and immutable values. const sym = Symbol("unique");

🔹 BigInt (ES11) – Large integers. let bigNumber = 12345678901234567890n;

2️⃣ Non-Primitive (Reference) Data Types (Stored by reference)

🔹 Object – Collection of key-value pairs. let person = { name: "Vivek", age: 25 };

🔹 Array – Ordered list of values. let colors = ["red", "green", "blue"];

🔹 Function – Block of reusable code. function greet() { return "Hello!"; }

🎯 Dynamic Typing in JavaScript

JavaScript is dynamically typed, meaning you don’t have to specify the type of variable explicitly. let data = "Hello"; // String data = 42; // Now it's a Number!

🚀 Conclusion

Variables and data types are the foundation of JavaScript programming. Understanding them helps in writing efficient and error-free code! 🔥

🎯 What's Next?

In the next blog, we will explore JavaScript Operators and Expressions in detail. Stay tuned! 🚀

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