JavaScript Code Quality Tools Comparison
eslint vs prettier vs standard vs xo
1 Year
eslintprettierstandardxoSimilar Packages:
What's JavaScript Code Quality Tools?

JavaScript code quality tools are essential for maintaining high standards in code readability, consistency, and overall quality. These tools help developers enforce coding standards, automatically format code, and catch potential errors before they become problematic. By integrating these tools into the development workflow, teams can ensure that their codebase remains clean, maintainable, and free from common pitfalls. Each tool has its unique features and philosophies, catering to different preferences and project requirements.

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eslint42,530,27925,2613.37 MB995 days agoMIT
prettier41,650,65249,6417.83 MB1,42714 days agoMIT
standard380,66429,176164 kB1233 months agoMIT
xo88,3957,71368 kB6112 days agoMIT
Feature Comparison: eslint vs prettier vs standard vs xo

Configuration Flexibility

  • eslint:

    ESLint offers extensive configuration options, allowing developers to customize rules, set environments, and define plugins tailored to their specific needs. This flexibility makes it suitable for a wide range of projects and coding styles.

  • prettier:

    Prettier is designed to require minimal configuration, focusing on enforcing a consistent code style with sensible defaults. While it can be configured to some extent, its opinionated nature means that most users will benefit from using it without extensive adjustments.

  • standard:

    Standard is completely zero-config, meaning it comes with a predefined set of rules that cannot be changed. This simplicity is beneficial for teams that want to avoid configuration overhead and adhere to a consistent style without debate.

  • xo:

    XO provides a balanced approach with sensible defaults and some configurable options. It aims to enforce best practices while still allowing for some customization, making it a good middle ground for teams.

Integration with Build Tools

  • eslint:

    ESLint integrates seamlessly with various build tools and IDEs, enabling real-time linting during development. It can be easily incorporated into CI/CD pipelines to ensure code quality before merging changes.

  • prettier:

    Prettier can be integrated into build processes and editors, allowing for automatic code formatting on save or during builds. This ensures that all code adheres to the same formatting rules consistently across the project.

  • standard:

    Standard can be integrated into build tools and CI environments, but its zero-config nature means it may require additional setup for specific integrations. It is straightforward to use in most scenarios without much overhead.

  • xo:

    XO supports integration with various build tools and editors, providing real-time feedback during development. It can also be used in CI environments to enforce code quality checks.

Community and Ecosystem

  • eslint:

    ESLint has a large and active community, with numerous plugins and extensions available for various frameworks and libraries. This extensive ecosystem allows developers to enhance their linting experience significantly.

  • prettier:

    Prettier also has a robust community and is widely adopted across many projects. Its popularity has led to numerous integrations with other tools and platforms, making it a standard choice for code formatting.

  • standard:

    Standard has a smaller community compared to ESLint but is still widely used. Its simplicity and zero-config approach have garnered a dedicated user base, especially among those who prefer convention over configuration.

  • xo:

    XO is a newer tool with a growing community. While it may not have as many plugins as ESLint, it is designed to be modern and user-friendly, appealing to developers looking for a straightforward linting solution.

Learning Curve

  • eslint:

    ESLint has a steeper learning curve due to its extensive configuration options and flexibility. New users may need time to understand how to set up and customize their linting rules effectively.

  • prettier:

    Prettier is easy to learn and use, as it focuses solely on formatting and requires minimal configuration. Developers can quickly adopt it without needing to understand complex rules.

  • standard:

    Standard is very easy to pick up since it requires no configuration. Developers can start using it immediately, making it a great choice for teams looking for simplicity.

  • xo:

    XO has a moderate learning curve, as it offers some configuration options while still being user-friendly. Developers familiar with ESLint will find it relatively easy to adapt.

Error Detection

  • eslint:

    ESLint excels in error detection, identifying a wide range of issues from stylistic problems to potential bugs in the code. Its ability to catch errors early in the development process is one of its key strengths.

  • prettier:

    Prettier focuses primarily on formatting rather than error detection. While it ensures consistent code style, it does not catch logical errors or potential bugs in the code.

  • standard:

    Standard provides basic error detection based on its predefined rules, but it may not catch as many issues as ESLint due to its limited configurability.

  • xo:

    XO offers good error detection capabilities, combining some of the best practices from ESLint while maintaining a simpler setup. It helps catch common issues while promoting a clean code style.

How to Choose: eslint vs prettier vs standard vs xo
  • eslint:

    Choose ESLint if you need a highly configurable linter that allows you to define your own rules and integrate with various plugins for specific frameworks or libraries. ESLint is ideal for teams that want to enforce custom coding standards and catch a wide range of issues in their code.

  • prettier:

    Choose Prettier if your primary goal is to maintain consistent code formatting across your project with minimal configuration. Prettier is opinionated and focuses solely on formatting, making it perfect for teams that want to avoid debates over code style and ensure uniformity in code appearance.

  • standard:

    Choose Standard if you prefer a zero-configuration approach to JavaScript coding standards. Standard enforces a set of predefined rules without the need for configuration files, making it suitable for projects where simplicity and convention over configuration is desired.

  • xo:

    Choose XO if you want a modern linter with a focus on simplicity and a built-in set of rules that align with best practices. XO also supports TypeScript and offers a straightforward setup, making it a great choice for projects that want to enforce quality without extensive configuration.

README for eslint

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ESLint

Website | Configure ESLint | Rules | Contribute to ESLint | Report Bugs | Code of Conduct | Twitter | Discord | Mastodon

ESLint is a tool for identifying and reporting on patterns found in ECMAScript/JavaScript code. In many ways, it is similar to JSLint and JSHint with a few exceptions:

  • ESLint uses Espree for JavaScript parsing.
  • ESLint uses an AST to evaluate patterns in code.
  • ESLint is completely pluggable, every single rule is a plugin and you can add more at runtime.

Table of Contents

  1. Installation and Usage
  2. Configuration
  3. Version Support
  4. Code of Conduct
  5. Filing Issues
  6. Frequently Asked Questions
  7. Releases
  8. Security Policy
  9. Semantic Versioning Policy
  10. Stylistic Rule Updates
  11. License
  12. Team
  13. Sponsors
  14. Technology Sponsors

Installation and Usage

Prerequisites: Node.js (^18.18.0, ^20.9.0, or >=21.1.0) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)

You can install and configure ESLint using this command:

npm init @eslint/config@latest

After that, you can run ESLint on any file or directory like this:

npx eslint yourfile.js

Configuration

You can configure rules in your eslint.config.js files as in this example:

export default [
    {
        files: ["**/*.js", "**/*.cjs", "**/*.mjs"],
        rules: {
            "prefer-const": "warn",
            "no-constant-binary-expression": "error"
        }
    }
];

The names "prefer-const" and "no-constant-binary-expression" are the names of rules in ESLint. The first value is the error level of the rule and can be one of these values:

  • "off" or 0 - turn the rule off
  • "warn" or 1 - turn the rule on as a warning (doesn't affect exit code)
  • "error" or 2 - turn the rule on as an error (exit code will be 1)

The three error levels allow you fine-grained control over how ESLint applies rules (for more configuration options and details, see the configuration docs).

Version Support

The ESLint team provides ongoing support for the current version and six months of limited support for the previous version. Limited support includes critical bug fixes, security issues, and compatibility issues only.

ESLint offers commercial support for both current and previous versions through our partners, Tidelift and HeroDevs.

See Version Support for more details.

Code of Conduct

ESLint adheres to the OpenJS Foundation Code of Conduct.

Filing Issues

Before filing an issue, please be sure to read the guidelines for what you're reporting:

Frequently Asked Questions

Does ESLint support JSX?

Yes, ESLint natively supports parsing JSX syntax (this must be enabled in configuration). Please note that supporting JSX syntax is not the same as supporting React. React applies specific semantics to JSX syntax that ESLint doesn't recognize. We recommend using eslint-plugin-react if you are using React and want React semantics.

Does Prettier replace ESLint?

No, ESLint and Prettier have different jobs: ESLint is a linter (looking for problematic patterns) and Prettier is a code formatter. Using both tools is common, refer to Prettier's documentation to learn how to configure them to work well with each other.

What ECMAScript versions does ESLint support?

ESLint has full support for ECMAScript 3, 5, and every year from 2015 up until the most recent stage 4 specification (the default). You can set your desired ECMAScript syntax and other settings (like global variables) through configuration.

What about experimental features?

ESLint's parser only officially supports the latest final ECMAScript standard. We will make changes to core rules in order to avoid crashes on stage 3 ECMAScript syntax proposals (as long as they are implemented using the correct experimental ESTree syntax). We may make changes to core rules to better work with language extensions (such as JSX, Flow, and TypeScript) on a case-by-case basis.

In other cases (including if rules need to warn on more or fewer cases due to new syntax, rather than just not crashing), we recommend you use other parsers and/or rule plugins. If you are using Babel, you can use @babel/eslint-parser and @babel/eslint-plugin to use any option available in Babel.

Once a language feature has been adopted into the ECMAScript standard (stage 4 according to the TC39 process), we will accept issues and pull requests related to the new feature, subject to our contributing guidelines. Until then, please use the appropriate parser and plugin(s) for your experimental feature.

Which Node.js versions does ESLint support?

ESLint updates the supported Node.js versions with each major release of ESLint. At that time, ESLint's supported Node.js versions are updated to be:

  1. The most recent maintenance release of Node.js
  2. The lowest minor version of the Node.js LTS release that includes the features the ESLint team wants to use.
  3. The Node.js Current release

ESLint is also expected to work with Node.js versions released after the Node.js Current release.

Refer to the Quick Start Guide for the officially supported Node.js versions for a given ESLint release.

Where to ask for help?

Open a discussion or stop by our Discord server.

Why doesn't ESLint lock dependency versions?

Lock files like package-lock.json are helpful for deployed applications. They ensure that dependencies are consistent between environments and across deployments.

Packages like eslint that get published to the npm registry do not include lock files. npm install eslint as a user will respect version constraints in ESLint's package.json. ESLint and its dependencies will be included in the user's lock file if one exists, but ESLint's own lock file would not be used.

We intentionally don't lock dependency versions so that we have the latest compatible dependency versions in development and CI that our users get when installing ESLint in a project.

The Twilio blog has a deeper dive to learn more.

Releases

We have scheduled releases every two weeks on Friday or Saturday. You can follow a release issue for updates about the scheduling of any particular release.

Security Policy

ESLint takes security seriously. We work hard to ensure that ESLint is safe for everyone and that security issues are addressed quickly and responsibly. Read the full security policy.

Semantic Versioning Policy

ESLint follows semantic versioning. However, due to the nature of ESLint as a code quality tool, it's not always clear when a minor or major version bump occurs. To help clarify this for everyone, we've defined the following semantic versioning policy for ESLint:

  • Patch release (intended to not break your lint build)
    • A bug fix in a rule that results in ESLint reporting fewer linting errors.
    • A bug fix to the CLI or core (including formatters).
    • Improvements to documentation.
    • Non-user-facing changes such as refactoring code, adding, deleting, or modifying tests, and increasing test coverage.
    • Re-releasing after a failed release (i.e., publishing a release that doesn't work for anyone).
  • Minor release (might break your lint build)
    • A bug fix in a rule that results in ESLint reporting more linting errors.
    • A new rule is created.
    • A new option to an existing rule that does not result in ESLint reporting more linting errors by default.
    • A new addition to an existing rule to support a newly-added language feature (within the last 12 months) that will result in ESLint reporting more linting errors by default.
    • An existing rule is deprecated.
    • A new CLI capability is created.
    • New capabilities to the public API are added (new classes, new methods, new arguments to existing methods, etc.).
    • A new formatter is created.
    • eslint:recommended is updated and will result in strictly fewer linting errors (e.g., rule removals).
  • Major release (likely to break your lint build)
    • eslint:recommended is updated and may result in new linting errors (e.g., rule additions, most rule option updates).
    • A new option to an existing rule that results in ESLint reporting more linting errors by default.
    • An existing formatter is removed.
    • Part of the public API is removed or changed in an incompatible way. The public API includes:
      • Rule schemas
      • Configuration schema
      • Command-line options
      • Node.js API
      • Rule, formatter, parser, plugin APIs

According to our policy, any minor update may report more linting errors than the previous release (ex: from a bug fix). As such, we recommend using the tilde (~) in package.json e.g. "eslint": "~3.1.0" to guarantee the results of your builds.

Stylistic Rule Updates

Stylistic rules are frozen according to our policy on how we evaluate new rules and rule changes. This means:

  • Bug fixes: We will still fix bugs in stylistic rules.
  • New ECMAScript features: We will also make sure stylistic rules are compatible with new ECMAScript features.
  • New options: We will not add any new options to stylistic rules unless an option is the only way to fix a bug or support a newly-added ECMAScript feature.

License

FOSSA Status

Team

These folks keep the project moving and are resources for help.

Technical Steering Committee (TSC)

The people who manage releases, review feature requests, and meet regularly to ensure ESLint is properly maintained.

Nicholas C. Zakas's Avatar
Nicholas C. Zakas
Francesco Trotta's Avatar
Francesco Trotta
Milos Djermanovic's Avatar
Milos Djermanovic

Reviewers

The people who review and implement new features.

唯然's Avatar
唯然
Nitin Kumar's Avatar
Nitin Kumar

Committers

The people who review and fix bugs and help triage issues.

Josh Goldberg ✨'s Avatar
Josh Goldberg ✨
Tanuj Kanti's Avatar
Tanuj Kanti

Website Team

Team members who focus specifically on eslint.org

Amaresh  S M's Avatar
Amaresh S M
Strek's Avatar
Strek
Percy Ma's Avatar
Percy Ma

Sponsors

The following companies, organizations, and individuals support ESLint's ongoing maintenance and development. Become a Sponsor to get your logo on our READMEs and website.

Platinum Sponsors

Automattic Airbnb

Gold Sponsors

trunk.io

Silver Sponsors

SERP Triumph JetBrains Liftoff American Express Workleap

Bronze Sponsors

Cybozu Syntax WordHint Anagram Solver Icons8 Discord GitBook Nx Mercedes-Benz Group HeroCoders

Technology Sponsors

Technology sponsors allow us to use their products and services for free as part of a contribution to the open source ecosystem and our work.

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