How do I make XO use spaces instead of tabs?

Use the --space flag when running XO or set space: true in your xo.config.js file. You can specify the number of spaces, like space: 4, for custom indentation without messing with ESLint rule configs.

XO or ESLint: which is better for a new project?

Choose XO if you want opinionated defaults with minimal setup, as it bundles useful plugins and handles TypeScript automatically. Use ESLint directly if you need fine-grained control over every rule or have highly specific custom requirements.

Can XO lint Vue.js components?

Yes, but it requires manual setup: install eslint-plugin-vue and spread its recommended config in your xo.config.js. This adds Vue linting rules, though it's not zero-config like core XO features.

How do I ignore a specific folder in XO?

Add the folder to the ignores array in your xo.config.js, or use the --ignore flag in the CLI. For example, ignores: ['dist/'] to exclude build directories, and you can negate defaults with patterns like '!vendor/**'.

Does XO work with Prettier for code formatting?

Yes, set the prettier option to true in config to format with Prettier, or 'compat' to disable conflicting rules and use Prettier separately. XO merges its defaults with your Prettier config, but contradicting options will throw an error.

What's the difference between XO and Standard JS?

XO is more pragmatic and configurable, with sensible defaults that can be overridden, while Standard enforces a fixed style without configuration. XO also includes more plugins like unicorn and better TypeScript support out of the box.

XO — Zero-Config ESLint Wrapper

What is XO?

XO is an opinionated linter for JavaScript and TypeScript that wraps ESLint with curated defaults to enforce consistent code style. It requires minimal configuration, automatically lints all relevant files, and includes useful plugins to catch common issues. The tool helps teams avoid style debates by providing a sensible baseline that 'just works' while remaining fully configurable.

Target Audience

JavaScript and TypeScript developers, especially those working in teams who want to enforce code style consistency without spending time configuring ESLint rules. It's ideal for projects seeking a 'batteries-included' linting setup.

Value Proposition

Developers choose XO because it reduces setup time to near zero with smart defaults, includes a curated set of modern ESLint plugins out of the box, and offers automatic fixes for many issues. Its pragmatic approach balances strong opinions with configurability, making it easier to maintain consistent code across projects.

❤️ JavaScript/TypeScript linter (ESLint wrapper) with great defaults

Use Cases

Best For

Teams adopting a consistent code style without lengthy configuration debates
JavaScript/TypeScript projects wanting a 'batteries-included' linting setup
Enforcing readable code with automatic fixes for common style issues
Projects using TypeScript that need automatic tsconfig handling
Integrating linting into editors and build tools with minimal effort
Incrementally adopting stricter linting rules in large codebases

Not Ideal For

Projects entrenched in CommonJS modules, as XO requires ESM adoption
Teams with existing, finely-tuned ESLint configurations who prefer full control over rule selection
Developers seeking a minimal linter without bundled plugins like unicorn or import-x

Pros & Cons

Pros

Zero-Configuration Setup

XO works immediately by linting all JS/TS files with sensible defaults, ignoring common paths automatically, so you can enforce code style without any initial setup.

Comprehensive Plugin Bundle

It includes powerful ESLint plugins like unicorn and import-x out of the box, catching a wide range of code quality issues without manual installation or configuration.

Automatic TypeScript Handling

XO seamlessly lints TypeScript files, automatically detecting and using tsconfig.json, eliminating the need for separate TypeScript linting setup or complex parser options.

Performance Optimizations

With built-in caching, XO speeds up subsequent lint runs in large projects by reusing previous results, making it efficient for continuous integration workflows.

Cons

ESM-Only Requirement

XO mandates that your project uses ESM modules, which forces a migration from CommonJS and can be a significant barrier for legacy codebases or tools not supporting ESM.

Complex Customization

While zero-config for basics, overriding defaults or adding framework-specific linting requires understanding and managing ESLint's flat config, which can be daunting and error-prone.

Bundled Opinion Overhead

The included plugins and strict defaults, like enforcing semicolons or tab indentation, might impose rules that some teams find unnecessary, requiring explicit configuration to disable or adjust.

What is XO?

Target Audience

Value Proposition

Use Cases

Best For

Teams adopting a consistent code style without lengthy configuration debates
JavaScript/TypeScript projects wanting a 'batteries-included' linting setup
Enforcing readable code with automatic fixes for common style issues
Projects using TypeScript that need automatic tsconfig handling
Integrating linting into editors and build tools with minimal effort
Incrementally adopting stricter linting rules in large codebases

Not Ideal For

Projects entrenched in CommonJS modules, as XO requires ESM adoption
Teams with existing, finely-tuned ESLint configurations who prefer full control over rule selection
Developers seeking a minimal linter without bundled plugins like unicorn or import-x

Pros & Cons

Pros

Zero-Configuration Setup

XO works immediately by linting all JS/TS files with sensible defaults, ignoring common paths automatically, so you can enforce code style without any initial setup.

Comprehensive Plugin Bundle

It includes powerful ESLint plugins like unicorn and import-x out of the box, catching a wide range of code quality issues without manual installation or configuration.

Automatic TypeScript Handling

XO seamlessly lints TypeScript files, automatically detecting and using tsconfig.json, eliminating the need for separate TypeScript linting setup or complex parser options.

Performance Optimizations

With built-in caching, XO speeds up subsequent lint runs in large projects by reusing previous results, making it efficient for continuous integration workflows.

Cons

ESM-Only Requirement

XO mandates that your project uses ESM modules, which forces a migration from CommonJS and can be a significant barrier for legacy codebases or tools not supporting ESM.

Complex Customization

While zero-config for basics, overriding defaults or adding framework-specific linting requires understanding and managing ESLint's flat config, which can be daunting and error-prone.

Bundled Opinion Overhead

The included plugins and strict defaults, like enforcing semicolons or tab indentation, might impose rules that some teams find unnecessary, requiring explicit configuration to disable or adjust.

XO

What is XO?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

XO

What is XO?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?