How do I install and use Putout in my project?

Install Putout via npm with 'npm i putout -D', then run it on directories like 'putout lib' to lint or add '--fix' to apply transformations. It requires Node.js 16 or higher and supports ESLint config files for easy setup.

Putout or ESLint: which one is better for my code?

Choose Putout if you need automated code refactoring and transformations, like converting CommonJS to ESM. ESLint is better for teams that only want stylistic linting without code changes, as Putout is more aggressive in its fixes.

Can Putout automatically fix syntax errors?

Yes, Putout can fix certain syntax errors automatically, as mentioned in its features. It uses built-in transformations to correct common issues, going beyond typical linting to improve code correctness.

How to write a custom plugin for Putout?

Create a plugin by defining 'report' and 'replace' functions in a simple format, like the remove-debugger example. Plugins can be placed in a rules directory or published as npm packages, leveraging Putout's declarative syntax.

Does Putout work with TypeScript and JSX files?

Yes, Putout supports TypeScript and JSX through its processors, allowing linting and transformation of .ts, .tsx, and .jsx files. You need to enable the TypeScript processor in configuration for full functionality.

Is Putout safe to use on production codebases?

Use with caution: commit your code before running Putout with --fix, as recommended in the README, and review changes thoroughly. Its transformations are powerful but can be intrusive, so testing in a controlled environment is advised.

PutOut — Pluggable JS Linter & Transformer

What is PutOut?

Putout is a pluggable JavaScript linter and code transformer that acts as a drop-in replacement for ESLint. It not only identifies code issues but also performs automated transformations to fix them, supporting a wide range of file types including JavaScript, TypeScript, JSX, Markdown, YAML, TOML, and JSON. It solves the problem of maintaining code quality through declarative, automated refactoring.

Target Audience

JavaScript and TypeScript developers looking to automate code quality improvements, enforce best practices, and modernize codebases across multiple file formats. It's especially useful for teams managing large codebases who need consistent, automated refactoring.

Value Proposition

Developers choose Putout over alternatives because it combines linting with powerful, automated code transformations. Unlike ESLint, it can make more drastic changes to code, such as converting CommonJS to ESM or fixing reference errors, all through a simple, plugin-based architecture.

🐊 Pluggable and configurable JavaScript Linter, code transformer and formatter with superpowers 💪: built-in support of js, jsx, ts, markdown, yaml, toml, json and ignore. Write declarative codemods in a simplest possible way 😏

Use Cases

Best For

Automated refactoring of large JavaScript/TypeScript codebases
Converting CommonJS modules to ES modules
Enforcing consistent code style across multiple file types (JS, TS, Markdown, YAML, etc.)
Writing declarative codemods for custom code transformations
Fixing syntax errors and code smells automatically
Integrating as a drop-in replacement for ESLint with enhanced transformation capabilities

Not Ideal For

Projects requiring only stylistic linting without automated code changes
Teams heavily invested in ESLint's vast plugin ecosystem without Putout equivalents
Environments with strict change control policies that prohibit automated refactoring
Developers unfamiliar with abstract syntax trees who need simple rule configuration

Pros & Cons

Pros

Multi-Format Support

Putout lints and transforms JavaScript, TypeScript, JSX, Markdown, YAML, TOML, JSON, and ignore files, as highlighted in the Key Features, making it versatile for diverse codebases.

Declarative Codemods

Transformations are written with minimal code, such as the 5-line remove-debugger plugin example, simplifying custom rule creation compared to competitors.

ESLint Drop-in Replacement

It supports ESLint configuration files (.eslintrc.json, eslint.config.js) for seamless integration, acting as a direct substitute with enhanced capabilities.

Built-in Advanced Transformations

Includes rules like converting CommonJS to ESM, removing unused variables, and fixing syntax errors, automating refactors that ESLint avoids due to runtime behavior concerns.

Cons

Risk of Over-Transformation

Putout makes drastic code changes that could introduce bugs if not reviewed, as the README admits by recommending committing code before using --fix and cautioning about trust issues.

Complex Plugin Development

Creating custom plugins requires understanding of abstract syntax trees and Putout's operator system, which is more involved than writing ESLint rules, limiting accessibility for beginners.

Limited External Ecosystem

While Putout has many built-in plugins, its external plugin community is smaller than ESLint's, reducing the availability of community-driven extensions for niche use cases.

What is PutOut?

Target Audience

Value Proposition

Use Cases

Best For

Automated refactoring of large JavaScript/TypeScript codebases
Converting CommonJS modules to ES modules
Enforcing consistent code style across multiple file types (JS, TS, Markdown, YAML, etc.)
Writing declarative codemods for custom code transformations
Fixing syntax errors and code smells automatically
Integrating as a drop-in replacement for ESLint with enhanced transformation capabilities

Not Ideal For

Projects requiring only stylistic linting without automated code changes
Teams heavily invested in ESLint's vast plugin ecosystem without Putout equivalents
Environments with strict change control policies that prohibit automated refactoring
Developers unfamiliar with abstract syntax trees who need simple rule configuration

Pros & Cons

Pros

Multi-Format Support

Putout lints and transforms JavaScript, TypeScript, JSX, Markdown, YAML, TOML, JSON, and ignore files, as highlighted in the Key Features, making it versatile for diverse codebases.

Declarative Codemods

Transformations are written with minimal code, such as the 5-line remove-debugger plugin example, simplifying custom rule creation compared to competitors.

ESLint Drop-in Replacement

It supports ESLint configuration files (.eslintrc.json, eslint.config.js) for seamless integration, acting as a direct substitute with enhanced capabilities.

Built-in Advanced Transformations

Includes rules like converting CommonJS to ESM, removing unused variables, and fixing syntax errors, automating refactors that ESLint avoids due to runtime behavior concerns.

Cons

Risk of Over-Transformation

Putout makes drastic code changes that could introduce bugs if not reviewed, as the README admits by recommending committing code before using --fix and cautioning about trust issues.

Complex Plugin Development

Creating custom plugins requires understanding of abstract syntax trees and Putout's operator system, which is more involved than writing ESLint rules, limiting accessibility for beginners.

Limited External Ecosystem

While Putout has many built-in plugins, its external plugin community is smaller than ESLint's, reducing the availability of community-driven extensions for niche use cases.

PutOut

What is PutOut?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Open Source Alternative To

Frequently Asked Questions

Found a gem we're missing?

PutOut

What is PutOut?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Open Source Alternative To

Frequently Asked Questions

Found a gem we're missing?