DEV Community

Erasmus Kotoka
Erasmus Kotoka

Posted on

Do you understand variables : Let, Const and Ver in JavaScript? IF NO then let go πŸ˜‰

In JavaScript, variables are like containers that store data. There are three ways to create (or declare) these containers: var, let, and const.

Let’s look at what makes them different! 🌟

  1. var – The Old-School Way πŸ“œ

Scope: var works within the function it's declared in (function-scoped), so it can be used anywhere inside that function. 🌍

Hoisting: JavaScript "hoists" or moves var declarations to the top of the function, but only the declaration, not the value.

This can sometimes cause confusion. πŸ˜•

Example:


var name = "Alice"; // Variable declared with 'var'

Enter fullscreen mode Exit fullscreen mode
  1. let – The New Standard 🌱

Scope: let is block-scoped, which means it's only available inside the block (curly braces {}) where it’s declared.

This makes it more predictable. 🧱

Reassignable: You can change the value of a let variable if needed. πŸ“

Example:


let age = 25; // Variable declared with 'let'

age = 30;   // You can reassign it

Enter fullscreen mode Exit fullscreen mode
  1. const – The Permanent One πŸ”’
  • Scope: Like let, const is also block-scoped. ⛓️

  • Non-Reassignable: Once a value is assigned to a const variable, it can't be changed. This is used when you don’t want the value to change. ❌

Example:


const birthYear = 1995; // Variable declared with 'const'

birthYear = 2000; // Error! You can't change it

Enter fullscreen mode Exit fullscreen mode

When to Use Them:

Use let when you need to update the variable’s value later.

Use const when the value should stay the same (like a constant).

Avoid var in modern JavaScript because let and const are more reliable.

By understanding let, const, and var, you'll write cleaner, more predictable JavaScript! 🎯

COdeWith #KOToka

KEEPCOding

DOntGIVeUP

AWS Security LIVE!

Tune in for AWS Security LIVE!

Join AWS Security LIVE! for expert insights and actionable tips to protect your organization and keep security teams prepared.

Learn More

Top comments (0)

A Workflow Copilot. Tailored to You.

Pieces.app image

Our desktop app, with its intelligent copilot, streamlines coding by generating snippets, extracting code from screenshots, and accelerating problem-solving.

Read the docs

πŸ‘‹ Kindness is contagious

Discover a treasure trove of wisdom within this insightful piece, highly respected in the nurturing DEV Community enviroment. Developers, whether novice or expert, are encouraged to participate and add to our shared knowledge basin.

A simple "thank you" can illuminate someone's day. Express your appreciation in the comments section!

On DEV, sharing ideas smoothens our journey and strengthens our community ties. Learn something useful? Offering a quick thanks to the author is deeply appreciated.

Okay