Variable Scope JavaScript

Lexical Scope JavaScript

• What is a scope?

  • A scope is a certain region of a program where a defined variable exists & can be recognized & beyond that they cannot be recognized.

• What are the types of Scopes?

  • Global Scope
  • Block Scope
  • Functional Scope

• var is functional scoped

{
	var a = 5;
}

console.log(a); // 5

• let & const are block scoped

{
	let a = 5;
}

console.log(a); // ReferenceError: a is not defined

{
	let a = 5;
	console.log(a); // 5
}

{
	const a = 5;
}

console.log(a); // ReferenceError: a is not defined

{
	const a = 5;
	console.log(a); // 5
}