variables.md

⚑ 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.

☴ Overview:

1. var
2. let
3. const
4. comparison

✦ 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;

var x = 10;
console.log(x); // Output: 10

✦ Let:

It declares a block-scoped variable. The data can be accessible block level of the code.

Syntax: let variableName = value;

function myFunction() {
  let y = 5;
  console.log(y); // Output: 5
}

✦ Const:

It declares a constant variable whose value cannot be changed after it's assigned.

Syntax: const variableName = value;

const PI = 3.14159;
console.log(PI); // Output: 3.14159

✦ 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.

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