Best Practices for Writing Clean JavaScript Code

ElevatEd
Coding
March 25, 2025

Imagine you're sitting down to write some JavaScript for your website. You’ve got the logic in your head, the code ready to go, but after a few hours of coding, you look back at your work and realize it’s a mess. The code is disorganized, hard to read, and difficult to debug. As a developer, this is a common mistake. Clean code is essential for maintaining and scaling projects, and writing it from the start makes life a whole lot easier.

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In this blog, we'll walk you through some best practices for writing clean JavaScript code. Think of these tips as your toolkit for creating efficient, readable, and maintainable code. Let’s dive in!

Keep Your Code Simple and Concise

JavaScript, like any other language, thrives on simplicity. It’s tempting to use complex code to show off your skills, but the goal should be to write code that is simple and easy to understand for others (or even for yourself, a few months later).

For instance, consider the following example of a bad approach:

Javascript code

const total = a => a.reduce((sum, current) => sum + current, 0);

While it may work fine, this code is somewhat difficult to understand at first glance. It combines two operations (reducing and summing) into a single line. Now, let's break it down into something cleaner:

javascript

Copy code

const sumArray = (arr) => {

let sum = 0;

for (let i = 0; i < arr.length; i++) {

sum += arr[i];

}

return sum;

};

This version is much easier to read and follows the principle of simplicity. It's clear what’s happening without needing to parse complex logic.

Use Descriptive Variable and Function Names

Naming is one of the most important aspects of writing clean code. Imagine you come across a variable named x or tempData—what do these mean? Probably nothing. Good names give context.

For example, let’s say you're working on a user management system and need a function to check if a user is active. The name of the function should reflect its purpose:

Javascript code

function isUserActive(user) {

return user.status === 'active';

}

By naming the function isUserActive, it’s immediately clear what the function does. Avoid cryptic names like checkStat or activeChecker—clarity always wins.

Avoid Nested Loops and Conditions

Nested loops or conditions can make your code very difficult to follow, especially when there are multiple layers. Instead, try to reduce nesting by using early returns or breaking down complex logic into smaller functions.

Consider this bad example:

Javascript code

if (userIsLoggedIn) {

if (userHasPermission) {

if (userIsAdmin) {

showAdminPanel();

}

This code can be simplified by using early returns:

Javascript code

function showAdminPanel(user) {

if (!user.isLoggedIn) return;

if (!user.hasPermission) return;

if (!user.isAdmin) return;

// Proceed to show admin panel

console.log("Showing Admin Panel");

}

By reducing the nested conditions, the function becomes easier to read and maintain.

Keep Functions Small and Focused

In JavaScript, it’s a good idea to keep functions small and focused on a single task. This makes testing, debugging, and updating much easier. If a function does too much, consider breaking it into smaller, more manageable pieces.

Here’s an example of a bad function:

Javascript code

function processUser(user) {

validateUser(user);

saveUser(user);

sendWelcomeEmail(user);

logUserActivity(user);

// Other unrelated tasks...

}

This function is doing too many things. To clean it up, break it down into smaller functions:

Javascript code

function validateUser(user) { /* validation code */ }

function saveUser(user) { /* saving code */ }

function sendWelcomeEmail(user) { /* email code */ }

function logUserActivity(user) { /* logging code */ }

Now each function has a single responsibility, making it easier to maintain and understand.

Use Comments Wisely

While clean code should speak for itself, there are still situations where comments can be useful—especially when you're dealing with complex algorithms or tricky logic. However, don't overdo it. Excessive comments can clutter your code.

Good comment practice could look like this:

Javascript code

// Checks if the user is active

function isUserActive(user) {

return user.status === 'active';

}

This simple comment adds clarity to the function’s purpose without over-explaining. But remember, don’t use comments to explain obvious code—your goal is to make the code itself self-explanatory.

Consistent Formatting and Indentation

Consistency is key when writing clean JavaScript. Indentation, spacing, and braces should follow the same pattern throughout your code.

For example:

Javascript code

// Consistent indentation

function sum(a, b) {

return a + b;

}

// Inconsistent indentation (hard to follow)

function sum(a, b) {

return a + b;

}

A consistent style is easier to read, and most developers prefer 4 spaces per indentation level. Use ESLint or similar tools to help enforce coding standards across your projects.

Use ES6+ Features

JavaScript has evolved over time, and with ES6 and beyond, new features have been introduced to simplify writing clean code. Features like arrow functions, template literals, destructuring, and spread operators make your code more concise and readable.

For example, instead of writing:

Javascript code

function greet(name) {

return 'Hello, ' + name + '!';

}

You can use template literals:

Javascript code

const greet = (name) => `Hello, ${name}!`;

This makes the code cleaner and easier to read

Why Clean Code Matters

Writing clean JavaScript code is not just a good practice for developers; it’s essential for long-term project success. Clean code is more maintainable, less prone to bugs, and easier to collaborate on. Whether you’re working on a small project or a large-scale application, adhering to best practices can save you time and frustration.

If you want to learn more about writing clean JavaScript, 98th Percentile Live Coding Classes offer in-depth training on JavaScript best practices, where you can learn how to write professional, maintainable code. The classes provide real-world coding scenarios, interactive lessons, and personalized guidance to help you master JavaScript.

FAQs

Q1: What are the most common mistakes in JavaScript coding?
Ans: Common mistakes include writing overly complex code, not using descriptive names, and not following consistent formatting.

Q2: How can I improve my JavaScript coding skills?
Ans: Practice writing clean code, follow best practices, and take live coding classes to improve your skills.

Q3: What is the benefit of using ES6 features?
Ans: ES6 features make your code more concise, readable, and modern, improving both performance and maintainability.

Q4: Should I always use comments in my code?
Ans: Comments are useful for complex logic but should be avoided for obvious code. The goal is to write code that speaks for itself.

Q5: What is the best way to organize large JavaScript codebases?
Ans: Break your code into smaller, reusable functions and use modules or classes to organize related code logically.