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JavaScript Best Practices Every Developer Should Know

Technology Moment 66

JavaScript is a cornerstone of modern web development, empowering developers to craft dynamic and interactive experiences for users. However, writing functional code is just the beginning; ensuring code maintainability, scalability, and readability is equally essential, especially for beginner developers.

In this article, we’ll delve into crucial JavaScript best practices that developers should be well-versed in. We’ll examine common mistakes and illustrate improved approaches with code examples, highlighting the significance of each practice.

1. Using Meaningful Variable Names

Bad Practice 👎

let a = 10;
let b = 20;

function calculate(x, y) {
return x + y;

Good Practice 👍

const firstNumber = 10;
const secondNumber = 20;

function calculateSum(num1, num2) {
return num1 + num2;

Choosing descriptive variable names is like providing a clear roadmap for anyone reading your code. The “bad” example features cryptic variable names like a and b, leaving readers puzzled about their purpose. The "good" example, on the other hand, employs meaningful names such as firstNumber and secondNumber. Furthermore, the function calculateSum reveals its intention without needing any additional explanation. When code is understandable at a glance, collaboration becomes smoother and debugging is more efficient.

2. Avoiding Repeating Yourself

Bad Practice 👎

function greetUser() {
console.log("Welcome to our website!");

function sayGoodbye() {
console.log("Thanks for visiting!");

Good Practice 👍

function displayMessage(message1, message2) {

displayMessage("Hello!", "Welcome to our website!");
displayMessage("Goodbye!", "Thanks for visiting!");

Repeated code is not only inefficient but also a maintenance nightmare. The “bad” example showcases identical console.log statements scattered across multiple functions. The "good" example embraces the DRY (Don't Repeat Yourself) principle by introducing a single function, displayMessage, that accepts different messages as parameters. This approach enhances maintainability; should you need to modify the message format or content, you only need to do it in one place.

3. Eliminating Magical Numbers

Bad Practice 👎

function calculateArea(radius) {
return 3.14 * radius * radius;

Good Practice 👍

const PI = 3.14;

function calculateArea(radius) {
return PI * radius * radius;

Magical numbers, arbitrary constants embedded in code, can bewilder fellow developers. In the “bad” example, the value 3.14 appears without context, leaving readers to wonder about its significance. The "good" example introduces a named constantPI, which immediately clarifies the purpose of the value. Should you need to update the value of PI for more precision, you can do so in a single location, affecting the entire codebase.

4. One Function Should Do One Thing

Bad Practice 👎

function processUserData(user) {

Good Practice 👍

function processUserData(user) {

function sendWelcomeEmail(user) {
// Code to send the welcome email

Functions, like tools, are most effective when they have a single, well-defined purpose. The “bad” example conflates user data processing with sending welcome emails, violating the principle of single responsibility. By contrast, the “good” example separates these concerns into two functions, promoting modular code that’s easier to test, maintain, and reason about.

5. Creating More Abstractions

Bad Practice 👎

// Without abstraction
const areaOfRectangle = length * width;
const perimeterOfRectangle = 2 * (length + width);
const volumeOfBox = length * width * height;

Good Practice 👍

// With abstraction
function calculateAreaOfRectangle(length, width) {
return length * width;

function calculatePerimeterOfRectangle(length, width) {
return 2 * (length + width);

function calculateVolumeOfBox(length, width, height) {
return length * width * height;

Abstraction is like using building blocks to construct complex structures. In the “bad” example, calculations for a rectangle’s area, perimeter, and volume are performed directly, resulting in code that can be hard to grasp and maintain.

Enter the “good” example, where abstraction reigns supreme. We’ve crafted functions that encapsulate specific calculations. calculateAreaOfRectangle computes the area of a rectangle, calculatePerimeterOfRectangle handles the perimeter calculation, and calculateVolumeOfBox tackles the box's volume. By abstracting these calculations, you construct a toolbox of functions that can be applied as needed. This modular approach enhances code readability and maintainability. Should you need to modify a calculation, you do so in one function, ensuring consistent behavior throughout your code base.

Frequently Asked Questions

Photo by Tim Mossholder on Unsplash

What are JavaScript best practices, and why should developers follow them?

JavaScript best practices are guidelines and recommendations that help developers write efficient, readable, and maintainable code. Regardless of your experience level, following these practices leads to cleaner code, better collaboration, and more reliable software.

How do meaningful variable names improve code quality?

Meaningful variable names provide context and clarity to your code. They make it easier for you and others to understand the purpose of variables, functions, and classes. This practice enhances collaboration and reduces the likelihood of introducing bugs due to misunderstandings.

What is the role of abstraction in JavaScript development?

Abstraction involves simplifying complex operations by encapsulating them in reusable functions or components. This not only promotes code reusability but also enhances readability and maintainability. Abstraction makes it easier to manage intricate logic without cluttering your code.

Why is proper error handling important in JavaScript programming?

Proper error handling ensures that your application can gracefully handle unexpected scenarios. By using try-catch blocks and providing informative error messages, you improve user experience and make it easier to identify and fix issues during development and in production.

How does documenting code contribute to a better code base?

Documenting code with comments helps developers understand the purpose, inputs, and outputs of different parts of your code. This is valuable for both newcomers and experienced developers, as it speeds up the onboarding process and facilitates future updates or debugging.

What are “magical numbers” in JavaScript, and why should developers avoid them?

Magical numbers are hardcoded numeric values used directly in calculations or comparisons without explanation. Avoiding them improves code maintainability by defining these values as constants with meaningful names. This practice ensures that changes can be made easily and consistently across your codebase.

How does the single responsibility principle enhance code architecture?

The single responsibility principle suggests that each function or module should have a single, clearly defined purpose. This principle fosters modularity, making code easier to understand and maintain. By adhering to this principle, developers create a more organized and efficient codebase.

Can these JavaScript best practices be applied by developers of all skill levels?

Absolutely! These best practices are essential for developers of all experience levels. Whether you’re a beginner or an advanced developer, incorporating these practices into your coding habits will lead to improved code quality, better collaboration, and more successful projects.

Photo by Kevin Ku on Unsplash


By internalizing these JavaScript best practices, developers contribute to the creation of maintainable, scalable, and comprehensible codebases. These practices foster efficient collaboration, streamlined development processes, and the construction of robust web applications that stand the test of time.