Node.js was born in 2009, and ever since then, developers have been implementing the best practices in Node.js for web development framework platforms. 

It’s fast, asynchronous, uses a single-threaded model, and has a syntax easy to understand even for beginners.

But that doesn’t mean it’s a walk in the park; one can easily get stuck in some error which can quickly become your nightmare. 

To counter this, we have listed some of the essential practices in node.js, which will help you create efficient and sustainable Node.js applications.

With the implementation of these best practices, the app automatically can minimize JavaScript runtime errors and turn into a high-performance, robust node.js application. 

Error Handling Practices 

Using Async-Await or promises for error handling. (for API calls as well) 

It doesn’t take long for callbacks to spiral out of control when they are nested one after the other, which results in callback hell. At this point, your code will be pretty unreadable.

Instead, you can prevent all this by using a reputable promise library or async-await, enabling a much more compact and familiar code syntax like try-catch (should use .then).

Using built-in Error object. 

Having an error bring down the entire production is never a great experience.

Many throw errors as a string or some custom type which complicates the error handling logic and the interoperability between modules.

There are many ways available for developers to raise an error and resolve them.

They can use strings or even define custom types. Still, using a Built-in error object makes a uniform approach to handle errors within our source code and prevent loss of information.

Not only that, but it also provides a standard set of helpful information when an error occurs. (wrap functionality in .then followed by a catch block) 

Handle Errors Centrally 

Without one dedicated object for error handling, more significant are the chances for inconsistent error handling in Node.js projects: Every logic that handles errors like logging performance, sending mails regarding errors should be written in such a way so that all APIs, night-jobs, unit testing can debug messages and call this method whenever any error occurs. Not handling errors within a single place will lead to code duplication and improperly handled errors. 

Practices for Project Structure  

Start all projects with npm init 

Use ‘npm init’ when you start a new project. It will automatically generate a package.json file for your project that allows you to add a bunch of metadata to help others working on the project have the same setup as you.  

Layer your components

Layering is essential, and thus each component is designed to have ‘layers’ – a dedicated object for the web, logic, and data access code.

You can make an orderly division of performance issues and significantly differentiate processes from mock and test codes by layering. It is advisable to create reusable components. Write API calls, logic, services in separate files. 

Use config files

You must have a config.js file that will hold all configurations in a centralized way. This practice ensures that other developers can locate and adjust config values much more quickly and much more easily.

Having one centralized file ensures reusability of config values and can give a quick insight into the Node.js project and what technologies/services/libraries are available to use.

Organize your solution into components (into components, services, modules etc) 

 The worst large applications pitfall is managing a vast code base with hundreds of dependencies – such a monolith slows down developers as they try to incorporate new features. Instead, partition the entire codebase into smaller components so that each module gets its folder and is kept simple and small. 

   

 Code Style Practices 

Use Strict Equality operator (===) (check object equality wisely) 

The strict equality operator (===) checks whether its two operands are equal and return a Boolean value. Unlike the weaker equality operator (==), the strict equality operator always considers operands of different types, whereas == will compare two variables after converting them to a common type. There is no type-conversion in ===, and both variables must be of the same kind to be equal. 

Use Linting Packages 

Use popular linting tools like ESLint, the standard for checking possible code errors, identifying nitty-gritty spacing issues, and detecting serious code anti-patterns like developers throwing errors without classification.

Though ESLint can automatically fix code styles, other tools like prettier and beautify are more potent in formatting the fix and working with ESLint. 

• Do not use ‘True/ false’ largely for logic building instead use constants. 
• Have seperate file for Constants 
• Do not use heavy operation builtin functions 
• Check for null or undefined values  
• Use comments for @param, @return values for functions 
• Practice writing Comment in between 

Name your functions 

Name all functions, including closures and callbacks. Restrict the use of anonymous functions. Naming is especially useful when profiling a node app.

Naming all functions will allow you to quickly understand what you’re looking at when checking a memory snapshot. (use arrow function) 

Use Arrow functions 

More extended codes are more prone to bugs and cumbersome to read, so it is advisable to use Arrow functions which make the code more compact and keep the lexical context of the root function.

However, according to the best practices in Node.js, it is recommended to use async-await applications to stop using functional parameters when working with old APIs that can accept promises or call-backs. 

Other Points to remember

• Have a separate file for Constants. 

• Reduce the use of heavy operation built-in functions   

• Check for null or undefined values before use.  

• Write a comment to increase readability. Comments are always handy for understanding the code. 

Going To Production Practices 

Monitor 

Failure === disappointed customers. Simple 

At the fundamental level, monitoring means you can quickly identify when bad things happen at production, for example, by getting notified by email or Slack.

It is a game of finding out issues before customers do.

The market is overwhelmed with offers; thus, consider defining the basic metrics you must follow.

Then going over additional fancy features and choose the solution that ticks all boxes. 

Increase transparency using smart logging 

 Logs can be a dumb warehouse of debug statements or the enabler of a beautiful dashboard that tells the story of your app. It’s advisable to plan your logs from day 1.

A proper framework for collecting, storing, and analyzing logs can ensure that we extract the desired information when required. 

Install your packages with npm ci 

When installing packages, you must ensure that the production code uses the exact version of the packages you tested.

Run npm ci to strictly do a clean install of your dependencies matching package.json and package-lock.json. Using this command is recommended in automated environments such as continuous integration pipelines. 

npm ci is also fast—in some cases, twice as fast as using npm i, representing a significant performance improvement for all developers using continuous integration. 

Testing and Overall Quality Practice 

Write API (component) tests 

Most projects do not have any automated testing due to short timetables, or often the ‘testing project’ ran out of control and was discontinued.

It will help plan your project deadline so that all your developed functionality by developers can adhere to automated testing.

For that reason, prioritize and start with API testing, which is the easiest way to write and provides more coverage than unit testing.

We can mock database calls and make sure whether the last changes done by someone else are broken or not after implementing new features.

Have Unit tests and functional tests for maximum coverage

Code coverage tools come with features that tell us whether we have converted codes under test cases or not. Some frameworks also help identify a decrease in testing coverage and highlight testing mismatches. 

You can set a minimum limit of test coverage % before committing code to make sure most of the statements are covered.

Structure tests  

It shouldn’t feel like reading imperative code rather than HTML – a declarative experience when reading a test case. To achieve this, keep the AAA convention so the reader’s minds will parse the test intent effortlessly.

Structure your tests with three well-separated sections: Arrange, Act & Assert (AAA). 

Arrange contains all the data or parameters or expected output used in subsequent calls or comparing actual and expected results, Act calls actual implementation with all arranged parameters, Assert compares the actual result with the desired result.

This structure guarantees that the reader spends no brain CPU on understanding the test plan. 

Tag Your Tests 

There are multiple scenarios where we have to run tests like smoke testing before committing changes to a source control system or when the pull request generates.

We can do this by using tags on tests with different keywords. You can tag tests with keywords like #api #sanity so you can grep with your testing harness and summon the desired subset. 

Security Best Practices 

Embrace linter security rules 

Use security-related linter plug-ins such as ESlint-plugin-security to catch security vulnerabilities and issues as early as possible, preferably while you are writing the code.

Tools like ESLint provides a robust framework for eliminating a wide variety of potentially dangerous patterns in your code by catching security weaknesses like using eval, invoking a child process, or importing a literal module string (e.g., user input). 

Strong Authentication

Having a solid authentication system is necessary for any system security. The lack of authentication or broken authentication makes the system vulnerable on many fronts. These are the few steps you can take to build a robust authentication system: 

• Remember to avoid basic authentication and use standard authentication methods like OAuth, OpenID, etc. 

• When creating passwords, do not use the Node.js built-in crypto library; use Bcrypt or Scrypt. 

• Ensure to limit failed login attempts, and do not tell the user if the username or password is incorrect. 

• And be sure to implement 2FA authentication. If done correctly, it can increase the security of your application drastically. You can do it with modules like node-2fa or speakeasy. 

Limit direct SQL Injections

SQL injection attacks are among the most infamous attacks today; As the name suggests, a SQL injection attack happens when a hacker gets access and can execute SQL statements on your database.

Attackers often send in queries by a pretense of user inputs which forces the system under attack to involuntarily give up sensitive data/information.

A secure way of preventing injection attacks is by validating inputs coming from the user. You need to validate or escape values provided by the user.

How to do it strictly depends on the database you use and how you prefer it. Some database libraries for Node.js perform escaping automatically (for example, node-MySQL and mongoose). But you can also use more generic libraries like Sequelize or knex.

Run automatic vulnerability scanning 

The Node.js ecosystem consists of many different modules and libraries that you can install. It’s common to use many of them in your projects and creates a security issue; when using code written by someone else, you can’t be 100 percent sure that it’s secure.

To help with that, you should run frequent automated vulnerability scans. They allow you to find dependencies with known vulnerabilities.

Use tools like npm audit or snyk to track, monitor, and patch vulnerable dependencies. Integrate these tools with your CI setup so you catch vulnerabilities before making it to production. 

Implement HTTP response header 

Attackers could perform direct attacks on your application’s users, leading to significant security vulnerabilities. We can avoid these attacks by adding additional security-related HTTP headers to your application. You can use plug-ins like – Helmet, which will add even more headers to secure your application, and it is easy to configure. 

The helmet can implement eleven different header-based security for you with one line of code: 

app.use(helmet()); 

Now, these are some of the best practices that will improve your node.js sense and remind you, these practices are not just limited to amateurs but to the entire Node.js developer community – from specialists to newbies.  

And so, concluding with the generic coding practice, let me remind you to KISS – Keep it Simple and short 🙂 

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