Added variables

ag-sanjjeev · ag-sanjjeev · commit 431db41e9ca7 · 2024-09-05T13:13:21.000+05:30
diff --git a/README.md b/README.md
@@ -18,6 +18,7 @@ This repository contains Vanilla JavaScript topics and their notes to learn from
 		- [var](./docs/variables.md#-var)
 		- [let](./docs/variables.md#-let)
 		- [const](./docs/variables.md#-const)
+		- [comparison](./docs/variables.md#-comparison)
 	- [Data types](./docs/data-types.md)
 		- [primitive data types](./docs/data-types.md#primitive-data-types) 
 			- [numbers](./docs/data-types.md#-numbers)
diff --git a/docs/variables.md b/docs/variables.md
@@ -0,0 +1,64 @@
+## &#9873; Variables
+The variables in JavaScript allows to store data to the names. That can be used again in the code.
+
+*There are 3 common variables in JavaScript.*
+
+### &#9780; Overview:
+1. [var](#-var)
+2. [let](#-let)
+3. [const](#-const)
+4. [comparison](#-comparison)
+
+### &#10022; Var:
+It declares a function-scoped or globally scoped variable. The scope means accessibility of the data which can be accessible inside function or if defined globally can accessible through out of the code.
+
+*Syntax: `var variableName = value;`*
+
+```javascript
+var x = 10;
+console.log(x); // Output: 10
+```
+
+### &#10022; Let:
+It declares a block-scoped variable. The data can be accessible block level of the code.
+
+*Syntax: `let variableName = value;`*
+
+```javascript
+function myFunction() {
+  let y = 5;
+  console.log(y); // Output: 5
+}
+````
+
+### &#10022; Const:
+It declares a constant variable whose value cannot be changed after it's assigned.
+
+*Syntax: `const variableName = value;`*
+
+```javascript
+const PI = 3.14159;
+console.log(PI); // Output: 3.14159
+````
+
+### &#10022; Comparison:
+- Scope:
+  - `var`: Function-scoped or globally scoped.
+  - `let` and `const`: Block-scoped.
+- Redeclaration:
+  - `var`: Can be redeclared within the same scope.
+  - `let` and `const`: Cannot be redeclared within the same scope.
+- Reassignment:
+  - `var` and `let`: Can be reassigned.
+  - `const`: Cannot be reassigned.
+
+| var | let | const |
+| --- | --- | --- |
+|  For older JavaScript code or when you need function-scoped or globally scoped variables. | For declaring variables within blocks (e.g., functions, loops, conditionals) where you need block-scoped behavior. | For declaring variables that will not change their values, such as constants or immutable objects. This helps prevent accidental modifications and improves code readability. |
+
+---
+[&#8682; To Top](#-variables)
+
+[&#10094; Previous Topic](./basic-syntax.md) &emsp; [Next Topic &#10095;](./data-types.md)
+
+[&#8962; Goto Home Page](../README.md)
