Mastering ES6: Unveiling the Power of Let and Const in JavaScript

A Practical Guide to Declaring Variables in Modern JavaScript

Photo by Oleg Laptev on Unsplash

JavaScript, the language that powers the web, has evolved over the years, and ES6 (ECMAScript 2015) introduced several features that make our lives as developers easier and our code more robust.

In this article, we’ll shine a light on two essential additions: let and const. These seemingly simple keywords bring a breath of fresh air to variable declarations, offering clarity and flexibility. So, let's dive in.

The Rise of let and const

In the good old days of JavaScript, the only way to declare variables was using var. While var is still around, ES6 introduced let and const to provide developers with more control over variable scoping and immutability.

let: Embracing Block Scope

The introduction of let marked a shift towards a more predictable scoping mechanism in JavaScript. Unlike var, which is function-scoped, let is block-scoped. What does that mean? Well, variables declared with let are confined to the block, statement, or expression where they are defined.

function exampleLetScope() {
  if (true) {
    let x = 10;
    console.log(x); //…