Discover the Trick to Avoid Commas Automatically Added by Prettier with Real Code Instances

Table of content

  1. Introduction
  2. Understanding the problem
  3. Why Prettier adds commas automatically
  4. The trick to avoid commas with Real Code Instances
  5. Conclusion
  6. Further Reading
  7. Glossary


Prettier is a popular code formatter used to maintain consistent code styles across different projects and teams. However, one common issue that developers face while using Prettier is the automatic addition of commas, which can cause errors in the code. Commas are necessary in some cases, but they can also create issues when they are added unnecessarily. This subtopic will provide a solution to the problem by discovering a trick that avoids commas automatically added by Prettier with real code instances. By following this guide, developers can ensure that their code is formatted correctly and without any unnecessary issues caused by automatic comma insertion.

Understanding the problem

Prettier is a popular code formatter that automatically formats code to adhere to a specified set of rules. While it can be a helpful tool that ensures code consistency across a team or project, it can also be frustrating when it adds commas where they are not needed.

This problem arises when Prettier follows a set of grammar rules for JavaScript or other programming languages. For example, Prettier will add a comma after the last item in an array, even though it is not technically necessary. While this may seem like a small issue, it can create discrepancies in code styles that can impact code readability and communication among team members.

For developers who prefer to have their code formatted in a particular style, such errors can be problematic. This is especially true for developers who are new to Prettier or are unfamiliar with its rules.

To address this issue, developers need to understand how Prettier works and how it applies formatting rules to code. By gaining a deeper understanding of Prettier's rules and how it operates, they can avoid automatic comma additions and ensure consistent code style throughout their projects.

Why Prettier adds commas automatically

Prettier is a popular code formatter used by developers for formatting JavaScript code. One of the features that make Prettier popular is its ability to automatically add commas to the end of JavaScript objects and arrays. However, this feature can also be a source of frustration for some developers, who prefer to add commas manually.

So why does Prettier add commas automatically? The answer lies in the way that Prettier was designed. Prettier is designed to follow a strict set of rules for formatting code, which are based on best practices and industry standards. One of these rules is the requirement to add commas at the end of objects and arrays in order to make them easier to read and maintain.

For example, consider the following object:

const user = {
  name: 'John',
  age: 25,
  email: ''

With Prettier, this object would automatically be formatted as:

const user = {
  name: 'John',
  age: 25,
  email: '',

The addition of the comma at the end of the email property makes it easier to add or remove properties in the future without having to worry about whether or not a comma is needed.

Overall, while some developers may prefer to add commas manually, Prettier's automatic comma insertion feature is designed to make code more readable and maintainable, and is a key part of the tool's functionality.

The trick to avoid commas with Real Code Instances

One trick to avoid commas automatically added by Prettier is to use object shorthand syntax when defining object literals. This syntax allows you to create an object with key-value pairs without explicitly stating the key name. Instead, the key name is inferred from the variable name, so you don't have to include a colon and the key name followed by a comma.

For example, instead of writing:

const person = {
  name: 'John',
  age: 30,
  address: {
    street: '123 Main St',
    city: 'Anytown',
    state: 'CA',

You can use object shorthand syntax to write:

const name = 'John';
const age = 30;
const street = '123 Main St';
const city = 'Anytown';
const state = 'CA';

const person = {
  address: { street, city, state },

By using object shorthand syntax, you can avoid the need for commas in the object literal, which can help you avoid errors when Prettier automatically adds them.

Another trick to avoid commas is to use array spreads instead of the concat method when combining arrays. When you use the concat method, you have to remember to include a comma between the arrays, which can be easy to forget, especially if you're working with many arrays.

Instead, you can use the spread operator, which allows you to expand an array into individual elements. This can help you avoid adding commas manually between arrays.

Here's an example:

const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];

const combinedArray = [...arr1, ...arr2];

Using the spread operator to combine arrays can help you avoid issues with commas, and can also make your code more concise and easier to read.


In , avoiding commas automatically added by Prettier can be achieved with a few simple tricks. By understanding the configuration options available and knowing when to disable certain features, developers can customize Prettier to suit their specific needs. Moreover, understanding the rationale behind Prettier's automatic formatting can help developers write cleaner and more concise code, making code reviews faster and more efficient. It's important to note that while Prettier is a valuable tool for maintaining consistency and readability in code, it's not a substitute for careful programming practices. Ultimately, the success of Prettier and similar tools depends on developers' willingness to use them correctly and in combination with other best practices.

Further Reading

If you're interested in learning more about the nuances of code formatting and the role of tools like Prettier in the development process, there are a variety of resources available online. Here are a few to get you started:

  • Prettier documentation: The official Prettier documentation provides a comprehensive overview of the tool's features and how to configure it for your codebase. The documentation also includes examples of common formatting scenarios and how Prettier handles them.

  • JavaScript standards: The JavaScript community has established a number of formatting and style standards for code. Understanding these standards can help you write more readable and maintainable code, and can also help you configure tools like Prettier to better suit your needs. The JavaScript Style Guide is widely used in the community, but there are many others available as well.

  • Code formatting discussions: Online developer communities often have discussions on how to approach code formatting and the use of tools like Prettier. These discussions can be a great way to learn from others and explore different approaches to common problems. Some good places to look for these discussions include Stack Overflow, Reddit's programming language-specific subreddits, and developer forums.


Prettier: A code formatter that automatically formats code according to defined rules and formatting standards.

Commas: A punctuation mark used to indicate a separation of words, phrases, or clauses within a sentence.

Syntax tree: A structure that represents the syntax and structure of a program or code in a hierarchical format.

AST: An abbreviation for "Abstract Syntax Tree," a data structure used to represent the syntax of a programming language.

Trick: A technique or strategy used to accomplish a specific task or goal.

Automatic formatting: The process of automatically formatting code according to defined rules or standards, without requiring manual intervention.

Code instances: Examples of code used to illustrate a particular point or concept.

As a developer, I have experience in full-stack web application development, and I'm passionate about utilizing innovative design strategies and cutting-edge technologies to develop distributed web applications and services. My areas of interest extend to IoT, Blockchain, Cloud, and Virtualization technologies, and I have a proficiency in building efficient Cloud Native Big Data applications. Throughout my academic projects and industry experiences, I have worked with various programming languages such as Go, Python, Ruby, and Elixir/Erlang. My diverse skillset allows me to approach problems from different angles and implement effective solutions. Above all, I value the opportunity to learn and grow in a dynamic environment. I believe that the eagerness to learn is crucial in developing oneself, and I strive to work with the best in order to bring out the best in myself.
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