Five best practices for Node.js beginners

Introduction

Node.js, the server-side JS runtime, enjoys immense popularity among developers & companies. But starting out in this fast-paced world can be hard. To make your journey smooth and efficient, it’s important to follow some established best practices. These practices are especially useful if you’re a beginner in the world of Node.js.

Following best practices makes your code clearer and easier to work with, both for yourself and others. This means less time fixing bugs, more time building, and the confidence to create applications that last.

This article covers five essential best practices to get you ready for your Node.js development journey. Each practice will be explained clearly, with examples to help you understand. By using these practices, you’ll build a strong foundation for well-structured, easy-to-manage, and secure Node.js applications.

The five best practices we’ll cover are:

1. Mastering asynchronous programming: Understanding how Node.js works and using special tools to handle tasks without stopping everything.
2. Structuring code for clarity: Organizing your code in a way that makes it easy to read and change.
3. Handling errors effectively: Fixing problems smoothly, so your application keeps working.
4. Testing application: Building Confidence with Automated Tests. Writing special programs to check if your code works as expected.
5. Securing Your Applications: Safeguarding User Data and System Integrity. Understanding and using security rules to protect your applications from harm.

Let’s get started.

Note: This article is aimed for beginners. If you know Node.js already, you may not find anything new.

Best practice 1 — Mastering asynchronous programming

Node.js works differently than most programs. It can handle several tasks at once, without stopping everything. This makes it ideal for building fast and responsive applications, especially when waiting for things like online data or file reading.

This unique way of working is called “asynchronous programming.” Instead of waiting for tasks to finish one by one, Node.js tells your code what to do when a task is completed. While it might seem strange at first, learning asynchronous programming is crucial for becoming a skilled Node.js developer.

Imagine making a sandwich. You can wait for each ingredient to be ready before starting the next step (traditional way). Or, you can butter the bread while the meat cooks and chop the lettuce (asynchronous way). This lets you finish faster, even though some tasks take longer.

In Node.js, asynchronous programming works this way:

1. Start a task: Tell Node.js to do something, like getting data from a website.
2. Move on: Node.js doesn’t wait for the task to finish. It continues with other things.
3. Get notified: When the task is done, Node.js calls a special function you provided (think of it like a message).
4. Do something: Inside the function, write the code to handle the task’s result, like using the fetched data.

Here’s a simple code example to illustrate:

function fetchData(url, callback) {
  // Pretend to fetch data (wait 2 seconds)
  setTimeout(() => {
    const data = "This is the data from " + url;
    callback(data);
  }, 2000);
}

fetchData("https://example.com/data", (data) => {
  console.log("Data received:", data);
});

console.log("This will print before the data arrives!");

In this example, fetchData starts fetching data and then sends a "message" (called a callback) with the received data. Even though fetching takes time, the code below console.log("This will print before the data arrives!") can run because Node.js doesn't wait.

By understanding and using asynchronous programming effectively, you’ll build applications that are fast, responsive, and efficient. Remember, practice makes perfect, and mastering this key concept will unlock the true potential of Node.js!

Best practice 2 — Structuring code for clarity

In Node.js, keeping your code clean and organized is crucial for both you and others who might work on your project. This is where structuring your code for clarity comes in.

Think of structure as giving your code a logical & maintainable layout. This is essential for several reasons:

1. Readability: Clear structure makes your code easier to read for yourself and others, saving time and effort when understanding what it does.
2. Maintainability: When your code is organized, it’s easier to fix bugs, add new features, and update existing ones without worrying about breaking something else.
3. Collaboration: Working with others on a well-structured project is smoother and more efficient, as everyone understands where things are and how they connect.

Here are some key practices for structuring your Node.js code for clarity:

• Use folders and files: Group related code into folders. For example, have a folder for routes, models, utilities, and so on. Inside each folder, keep your code in separate files for specific tasks.
• Meaningful names: Choose descriptive names for your folders and files. Avoid generic names like “file1.js” and use names that clearly explain what the code inside does.
• Comments: Add comments to explain complex parts of your code, but avoid overdoing it. Comments should be clear and concise, providing just enough information for someone to understand the code’s purpose.
• Follow a style guide: Choose a popular style guide for Node.js, like Airbnb or Google, and stick to its formatting and naming conventions. This ensures consistency and makes your code easier to read for others familiar with the style guide.

Here’s an example of how you might structure a simple Node.js project:

project-name/
  |
  +-- src/
  |       +-- controllers/
  |       |     +-- users.js
  |       |     +-- posts.js
  |       +-- models/
  |       |     +-- user.js
  |       |     +-- post.js
  |       +-- routes/
  |       |     +-- index.js
  |       |     +-- users.js
  |       |     +-- posts.js
  |       +-- app.js
  |       +-- config.js
  |
  +-- public/
  |       +-- index.html
  |       +-- main.css
  |       +-- script.js
  |
  +-- package.json

In this example, the src folder contains all the source code, organized into subfolders for controllers, models, and routes. The public folder holds static assets like HTML, CSS, and JavaScript files. The app.js file is the main entry point for your application, and config.js stores configuration settings.

Best practice 3 — Handling errors effectively

Even the best-written code can encounter errors. In Node.js, unexpected things can happen, like failing network connections, missing files, or invalid user input. Without proper error handling, these errors can crash your application or confuse users. That’s where handling errors effectively comes in.

There are two main ways to handle errors in Node.js:

1. Try-Catch Blocks: A try-catch block lets you surround code that might cause errors with a "try" section and a "catch" section. If an error occurs in the "try" section, the "catch" section takes over and prevents the application from crashing. This allows you to handle the error gracefully, like displaying a user-friendly message or logging information for debugging.

2. Promises and Async/Await: When dealing with asynchronous code (tasks that happen over time), promises and async/await offer another way to handle errors. If an error happens while waiting for a promise, you can use .catch to handle it just like in a try-catch block. Async/await allows you to write asynchronous code in a more synchronous-like style, using try-catch blocks directly within async functions.

Here are some key practices for effective error handling in Node.js:

• Use specific error messages: Don’t just say “An error occurred.” Explain what went wrong in a clear and helpful way.
• Log errors: Record errors in a file or send them to a monitoring system for later analysis and debugging.
• Provide user feedback: Let users know something went wrong in a friendly and informative way, preventing confusion or frustration.
• Don’t ignore errors: Fix the root cause of errors whenever possible to prevent them from happening again.

Here’s a simple example of a try-catch block:

try {
  const data = fs.readFileSync("data.txt"); // Read a file
  console.log(data.toString());
} catch (error) {
  console.error("Error reading file:", error.message);
  // Handle the error gracefully, like displaying a message to the user
}

Best practice 4 — Testing application

Testing your code ensures that it works as expected and catching problems before they impact your users.

Think of testing as having someone else use your application and report any issues they encounter. Instead of relying on others, you write specific programs called tests that automatically run your code and see if it produces the correct results. This helps you find and fix bugs early, saving time and frustration later.

There are two main types of tests in Node.js:

1. Unit Tests: These tests check individual parts of your code, like functions and modules. They’re like taking your application apart and testing each component to ensure it works independently.

2. Integration Tests: These tests check how different parts of your code work together, like how your routes interact with your database.

Here are some key benefits of writing tests for your Node.js applications:

• Catch bugs early: Tests help you find and fix errors before they reach your users, leading to a more stable and reliable application.
• Refactor with confidence: When tests pass, you’re more confident making changes to your code without introducing new bugs.
• Improved documentation: Writing tests forces you to think clearly about how your code works, creating valuable documentation for yourself and others.

Writing tests might seem like extra work, but it’s an investment that pays off in the long run. Here’s a simple example of a unit test using the popular Mocha framework:

const assert = require('assert');

function add(a, b) {
  return a + b;
}

describe('add function', () => {
  it('should add two numbers correctly', () => {
    const result = add(2, 3);
    assert.equal(result, 5);
  });
});

As your application grows, update and expand your tests to ensure it continues to function as expected. By making testing a regular practice, you build confidence in your code, deliver high-quality applications, and save time and effort in the long run.

Best practice 5 — Securing Your Applications

Your Node.js applications require security to safeguard user data and system integrity.

By following security best practices, you create a strong shield that protects your application from malicious attacks and data breaches.

Here are some key threats that Node.js applications can face:

• Unauthorized access: Attackers might try to gain access to sensitive data like user passwords or credit card information.
• Data breaches: Hackers could exploit vulnerabilities to steal confidential information.
• Denial-of-service attacks: These attacks aim to overwhelm your application with traffic, making it unavailable to legitimate users.

Here are some crucial practices for securing your Node.js applications:

1. Validate user input: Never trust data received from users without properly validating it. This prevents attackers from injecting malicious code into your application.
2. Sanitize data output: Ensure data sent to users is properly sanitized to avoid vulnerabilities like cross-site scripting (XSS).
3. Use strong authentication: Implement robust user authentication mechanisms to prevent unauthorized access.
4. Keep software updated: Regularly update your application dependencies and Node.js itself to patch known vulnerabilities.
5. Choose secure libraries: Use well-maintained and secure libraries and frameworks for your development.

Remember, security is an ongoing process, not a one-time fix. By continuously staying informed about new threats and best practices, you can build secure applications that protect your users’ data and maintain their trust.

Here’s a simple example of validating user input using the validator library:

const validator = require('validator');

const username = req.body.username;

if (!validator.isAlphanumeric(username)) {
  throw new Error('Username must be alphanumeric characters only');
}

Here’s another example demonstrating secure password hashing using the popular bcrypt library:

const bcrypt = require('bcrypt');

const SALT_ROUNDS = 10;

async function hashPassword(password) {
  const salt = await bcrypt.genSalt(SALT_ROUNDS);
  const hashedPassword = await bcrypt.hash(password, salt);
  return hashedPassword;
}

async function comparePassword(password, hashedPassword) {
  return await bcrypt.compare(password, hashedPassword);
}

// Example usage:
const userPassword = "my_strong_password";
const hashedPassword = await hashPassword(userPassword);

// Later, user tries to login:
const loginPassword = "maybe_the_password";
const isMatch = await comparePassword(loginPassword, hashedPassword);

if (isMatch) {
  console.log("Login successful!");
} else {
  console.log("Incorrect password.");
}

Thanks for reading this article!