Difference between let, var and const with examples.

Introduction

In JavaScript, let, var, and const are three types of variable declarations that allow programmers to store values and reuse them later in their code. Each has its own characteristics, and the main difference between them lies in their scope and mutability.

var is the oldest type of variable declaration and was used in earlier versions of JavaScript. let and const were introduced in ES6 (ECMAScript 2015) and are considered more modern.

Here are the main differences between let, var, and const:

1. Scope

var variables are function-scoped, while let and const variables are block-scoped. This means that variables declared with var are accessible anywhere within the function in which they are declared, while variables declared with let and const are only accessible within the block in which they are declared.

Examples:

2. Mutability

Variables declared with let can be reassigned new values, while variables declared with const cannot be reassigned. Variables declared with var can also be reassigned.

Examples:

3.Hoisting

var declarations are hoisted to the top of their scope, while let and const declarations are not hoisted. This means that you can use a var variable before it is declared, but you cannot do the same with a let or const variable.

Examples:

Conclusion

In summary, let is used to declare variables that are block-scoped and can be reassigned, const is used to declare variables that are block-scoped and cannot be reassigned, and var is used to declare variables that are function-scoped and can be reassigned.