Node.js is a software platform that is popular for backend JavaScript development. When hiring Node.js developers, companies always investigate developers’ expertise. This is because when creating an application in Node.js any developer must follow certain programming practices to ensure code quality. So, how do Node.JS developers ensure code quality?

Developers save the exact version of the package in the package.json file

Developing a Node.js application means constantly adding new packages to extend its functionality. Usually, the following command is used for this:

npm install express –save

The npm manager installs the assigned package and captures the dependency in the package.json file as follows:

“express”: “^4.17.1”

“^4.17.1″” is the version of the package. The use of the “^” assumes that a value in the range “>=4.17.1 <5.0.0” is acceptable for the version.

This will become a problem if someone else uses the package.json file that was created with the “npm install” command to set up the application environment and install dependencies. If this occurs, the npm manager will ignore the version specified in package.json and install a newer package that might not work correctly in conjunction with the program.

To prevent package version conflicts, developers configure npm through the .npmrc configuration file, so that the exact version is automatically specified when installing packages. When someone else uses the package.json file to install dependencies, the npm manager will deliver the exact version of the package that was used during development.

Developers use a restart tool for the application

When programming in Node.js, developers have to manually stop and restart the application to apply even small changes made to the source code. While performing these monotonous actions, developers find that they get in the way of focusing on the task at hand.

To solve this problem, developers use tools that monitor the source code and automatically apply changes whenever they make edits to the code. Popular code monitoring programs in Node.js:

  • Nodemon. It automatically restarts the application whenever any code changes are made. Developers install the package from the npm library and then work with the program using “nodemon” on the command line (for example, by running “nodemon app” instead of “node app“).
  • Forever. It also provides the automatic restart that Nodemon does, but has more functionality. It can set the working directory and record logs which would normally be reflected in the file descriptor (stdout).
  • PM2. It is another process management tool. Compared to the first two, it gives developers more control and possibilities to manage processes in an application’s operational environment.

Developers use these tools even when the Node application is already serving visitors. If an execution error occurs, the utility will roll back the changes. Moreover, programs like these can be configured to automatically restart the application if the server goes down. This sometimes helps with non-serious crashes.

Developers use style guides

When there are several programmers involved in a project, their code style is bound to differ. This often interferes with teamwork. It is hard to resist reformatting the code to a certain developer`s liking if another developer does not like the style of his or her colleague. The developer will end up wasting a lot of valuable time on this pointless task.

Programmers like to argue about which style of JavaScript code is better. But this choice is mostly subjective. So, developers agree on or choose a ready-made code style guide before starting a project.

Developers use async/await syntax

When JavaScript first appeared, its asynchronous nature was realized through the use of callback functions. But, as every developer knows from experience, callback functions easily get out of hand when nested within each other. From this point on, the code becomes almost unreadable.

Nevertheless, JavaScript ES6 provides an opportunity to use async/await syntax. Therefore, every developer uses async/await syntax to ensure code quality.

Developers choose an appropriate logging tool

Developers know that console.log usage is a bad idea. Most of them forgot about using it at all for logging their applications. This is because the console.log method doesn’t offer enough options for configuring logging or filtering incoming information.

For Node.js, there are several frameworks specialized for logging. For example, Winston, Bunyan, and Pino.

In addition to the usual logging, they allow developers to divide log entries into levels. For example: “error”, “warning”, “information and debugging”.

Developers declare a variable using the const specifier

Applying a const specifier makes it impossible to reassign or reuse a variable after the first assignment. Thus, const forces developers to declare new variables with appropriate names. This makes the code cleaner and clearer.

But there are cases where developers want to be able to reassign a variable argument. Then developers use let. For example, with this specifier, developers have to declare an incremental variable inside a loop.

Before let was introduced in the ES6 standard, programmers used the var specifier. Some developers still use it in their code.

Developers don’t link the frontend to Node

Node.js serves all requests to the server in a single thread, which developers strive to use most efficiently. The quality of this optimization affects application performance.

A thread can become overloaded if Node.js is used to send out static content (HTML, CSS files, media files, etc.). This is unacceptable when working with dynamic content, which requires maximum use of components and logic of the running application. As a result of unbalanced resource allocation, application performance is markedly reduced.

To avoid imbalance, developers remove the task of static content processing from the Node server. To do this, they install third-party middleware, which serves the frontend to the users. For example, Nginx, S3, or CDN. Then Node is free to handle dynamic content without any loss of performance.

Developers don’t store information in the application

Developers put any kind of data from the application (user sessions, user data, cache) in external storage. They do not allow data to be stored in the application itself.

In other words, the application does not depend on any state (stateless protocol). It must be possible to stop the server at any time and restart it so that it does not affect the users. Alternatively, developers use serverless platforms, such as AWS Lambda, which assume operation with stateless protocol by default.

Developers use tools to analyze code coverage

Node-application testing is not one of the main ways to ensure code quality, since meeting this condition should already be implied by default. Using code coverage tools is one of the best practices to follow when developing with Node.js.

Code coverage analysis tools are used to determine the level of test coverage of a program. They detect and highlight the unchecked snippets.


In this article, we discussed the best programming practices Node.js developers follow. By following them, developers ensure code quality as well as make it more readable.

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