JavaScript — Style Guide: Writing Clean, Consistent & Maintainable Code

Introduction – Why Follow a JavaScript Style Guide?

Ever opened someone else’s JavaScript code and had no clue what was going on? 😵 Poorly styled code isn’t just hard to read — it’s error-prone, hard to maintain, and nearly impossible to scale in team environments.

A JavaScript Style Guide is a set of coding conventions and best practices that help developers write clean, consistent, and bug-free code. Whether you’re working solo or with a team, a style guide acts as a contract for how code should look and behave.

By the end of this article, you’ll understand:

• The most important JavaScript style rules (naming, spacing, structure)
• Popular style guides (Airbnb, Google, StandardJS)
• Tools to enforce and automate style consistency

Benefits of Using a JavaScript Style Guide

Key JavaScript Style Guide Rules

Let’s explore the most essential style rules to follow:

🐪 1. Use CamelCase for Variables & Functions

//  Good
let userName = 'Vaibhav';
function getUserData() {}

//  Bad
let user_name = 'Vaibhav';
function get_user_data() {}

Improves readability and matches JS conventions.

2. Use const and let Instead of var

const API_URL = 'https://api.example.com';
let userAge = 30;

Use const for values that don’t change and let for those that do.

3. Semicolons Are a Must (Unless Your Guide Says Otherwise)

//  Good
let score = 100;

//  Risky
let score = 100

JavaScript’s automatic semicolon insertion (ASI) can lead to bugs. Use semicolons for safety.

4. Consistent Indentation (2 or 4 Spaces)

function greet(name) {
  console.log(`Hello, ${name}`);
}

Choose either 2 or 4 spaces, and stick to it project-wide.

5. Use Single Quotes for Strings

const message = 'Hello World!';

Unless using template literals or needing to escape ', prefer single quotes.

6. Avoid Global Variables

//  Good (Encapsulated)
(function () {
  let internalCounter = 0;
})();

Global variables can be overwritten or conflict with other scripts.

7. Use Descriptive Variable & Function Names

//  Good
let currentUserScore = 92;

//  Bad
let x = 92;

Clear names help others understand code without extra comments.

8. Always Use Strict Mode

'use strict';

🚨 Prevents silent bugs and enforces cleaner syntax rules.

9. Remove Unused Code & Comments

//  Clean
function calculateTotal(a, b) {
  return a + b;
}

//  Cluttered
// function oldTotal() {
//   return a * 2;
// }

Keep codebase lean and maintainable by deleting dead code.

10. Use Arrow Functions for Anonymous Functions

//  Arrow function
const numbers = [1, 2, 3].map(n => n * 2);

More concise and preserves lexical this.

Popular JavaScript Style Guides

Pick a style guide and stick to it across your codebase.

Tools for Enforcing Style Consistency

1. ESLint

# Install
npm install eslint --save-dev

# Initialize config
npx eslint --init

ESLint can auto-detect problems and enforce style rules with plugins (e.g., Airbnb ESLint config).

2. Prettier

# Install
npm install --save-dev prettier

# Format all files
npx prettier --write .

🖌️ Prettier focuses on formatting (spacing, line wrapping) and integrates well with ESLint.

3. Combined Usage (ESLint + Prettier)

Use both for style enforcement (ESLint) and code formatting (Prettier).

npm install eslint-config-prettier eslint-plugin-prettier --save-dev

Configure .eslintrc to extend Prettier rules and avoid conflicts.

Summary – Write Cleaner JavaScript Today

Here’s a recap of what you’ve learned:

Follow consistent naming, spacing, and indentation
Use modern syntax (let, const, arrow functions)
Pick and enforce a style guide like Airbnb or StandardJS
Use ESLint and Prettier to automate style enforcement
Clean up your codebase regularly for readability and maintainability

A well-maintained code style improves collaboration, reduces bugs, and boosts professionalism in any project.

FAQs – JavaScript Style Guide

Why is a JavaScript style guide important?

It promotes code consistency, readability, and reduces the likelihood of bugs or misunderstandings among developers.

Which JavaScript style guide should I use?

Airbnb is the most popular, but Google’s guide or StandardJS are also great. Choose one that aligns with your team and project.

Can ESLint and Prettier work together?

Yes! ESLint checks for code quality, while Prettier formats code. Use them together for best results.

What’s the difference between formatting and linting?

Linting checks for logical and stylistic errors, formatting deals with how code looks (spacing, semicolons, etc.).

Should I enforce style rules in personal projects?

Yes — it’s a good habit and prepares you for collaborative work in professional environments.