Eslint-plugin-perfectionist NPM

ESLint Plugin Perfectionist

An ESLint plugin that sets rules to format your code and make it consistent.

This plugin defines rules for sorting various data, such as objects, imports, TypeScript types, enums, JSX props, Svelte attributes, etc. alphabetically, naturally, or by line length.

All rules are automatically fixable. It's safe!

Why

Sorting imports and properties in software development offers numerous benefits:

Readability: Finding declarations in a sorted, large list is a little faster. Remember that you read the code much more often than you write it.
Maintainability: Sorting imports and properties is considered a good practice in software development, contributing to code quality and consistency across the codebase.
Code Review and Collaboration: If you set rules that say you can only do things one way, no one will have to spend time thinking about how to do it.
Code Uniformity: When all code looks exactly the same, it is very hard to see who wrote it, which makes achieving the lofty goal of collective code ownership easier.
Aesthetics: This not only provides functional benefits, but also gives the code an aesthetic appeal, visually pleasing and harmonious structure. Take your code to a beauty salon!

Documentation

See docs.

Alphabetical Sorting

Sorting by Line Length

Installation

You'll first need to install ESLint v8.45.0 or greater:

npm install --save-dev eslint

Next, install eslint-plugin-perfectionist:

npm install --save-dev eslint-plugin-perfectionist

Usage

Add eslint-plugin-perfectionist to the plugins section of the ESLint configuration file and define the list of rules you will use.

Flat Config (`eslint.config.js`)

import perfectionist from 'eslint-plugin-perfectionist'

export default [
  {
    plugins: {
      perfectionist,
    },
    rules: {
      'perfectionist/sort-imports': [
        'error',
        {
          type: 'natural',
          order: 'asc',
        },
      ],
    },
  },
]

Legacy Config (`.eslintrc.js`)

module.exports = {
  plugins: [
    'perfectionist',
  ],
  rules: {
    'perfectionist/sort-imports': [
      'error',
      {
        type: 'natural',
        order: 'asc',
      }
    ]
  }
}

Configs

The easiest way to use eslint-plugin-perfectionist is to use ready-made configs. Config files use all the rules of the current plugin, but you can override them.

Flat Config (`eslint.config.js`)

import perfectionist from 'eslint-plugin-perfectionist'

export default [
  perfectionist.configs['recommended-natural'],
]

Legacy Config (`.eslintrc`)

module.exports = {
  extends: [
    'plugin:perfectionist/recommended-natural-legacy',
  ],
}

List of Configs

Name	Description
recommended-alphabetical	All plugin rules with alphabetical sorting in ascending order
recommended-natural	All plugin rules with natural sorting in ascending order
recommended-line-length	All plugin rules with sorting by line length in descending order
recommended-custom	All plugin rules with sorting by your own custom order

Rules

🔧 Automatically fixable by the --fix CLI option.

Name	Description	🔧
sort-array-includes	Enforce sorted arrays before include method	🔧
sort-classes	Enforce sorted classes	🔧
sort-decorators	Enforce sorted decorators	🔧
sort-enums	Enforce sorted TypeScript enums	🔧
sort-exports	Enforce sorted exports	🔧
sort-heritage-clauses	Enforce sorted `implements`/`extends` clauses	🔧
sort-imports	Enforce sorted imports	🔧
sort-interfaces	Enforce sorted interface properties	🔧
sort-intersection-types	Enforce sorted intersection types	🔧
sort-jsx-props	Enforce sorted JSX props	🔧
sort-maps	Enforce sorted Map elements	🔧
sort-modules	Enforce sorted modules	🔧
sort-named-exports	Enforce sorted named exports	🔧
sort-named-imports	Enforce sorted named imports	🔧
sort-object-types	Enforce sorted object types	🔧
sort-objects	Enforce sorted objects	🔧
sort-sets	Enforce sorted Set elements	🔧
sort-switch-case	Enforce sorted switch case statements	🔧
sort-union-types	Enforce sorted union types	🔧
sort-variable-declarations	Enforce sorted variable declarations	🔧

FAQ

Can I automatically fix problems in the editor?

Yes. To do this, you need to enable autofix in ESLint when you save the file in your editor. You may find instructions for your editor here.

Is it safe?

Overall, yes. We want to make sure that the work of the plugin does not negatively affect the behavior of the code. For example, the plugin takes into account spread operators in JSX and objects, comments to the code. Safety is our priority. If you encounter any problem, you can create an issue.

Why not use Prettier?

I love Prettier. However, this is not its area of responsibility. Prettier is used for formatting, and ESLint for styling. For example, changing the order of imports can affect how the code works (console.log calls, fetch, style loading). Prettier should not change the AST. There is a cool article about this: "The Blurry Line Between Formatting and Style" by @joshuakgoldberg.