Slango Eslint Configs (@slango.configs/eslint)

This package exposes eslint configurations for easy setup, the following presets are available:

| Name | Description | Includes | | -------------------- | --------------------------------------------------------------------------------------------------- | -------------------------------- | | javascript-node | Intended to be used for tooling javascript files (eg: eslint.confg.js, linte-staged.config.js, ...) | - | | typescript | Intended to be used for typescript based projects and libraries | javascript-node | | typescript-node | Intended to be used for typescript based node projects and libraries | javascript-node + typescript | | typescript-browser | Intended to be used for typescript based browser projects and libraries | javascript-node + typescript | | typescript-next | Intended to be used for typescript based next.js applications | javascript-node + typescript |

Included plugins/configs

| Name | Available in Preset | Description | | ---------------------------------------------------------------------------------------------------------------- | ------------------------ | -------------------------------------------------------- | | @eslint/js recommended | all | @eslint/js official recommended configuration | | eslint-plugin-eslint-comments recommended | all | Comments from @eslint-community for comments | | eslint-plugin-perfectionist | all | Configurable sorting rules with tiered strictness levels | | eslint-plugin-regex recommended | all | Recommended config from regexp-eslint-plugin | | eslint-plugin-prettier recommended | all | Prettier official eslint plugin's recommended config | | eslint-plugin-import recommended | all | Prettier official eslint plugin's recommended config | | typescript-eslint recommendedTypeChecked | all typescript configs | Typescript Eslint type checked recommended config | | next/core-web-vitals | typescript-next | Next.js official eslint config |

Usage

Add @slango.configs/eslint to your package.json as a dev dependency, then create a eslint.config.js file in the package.

Unless you want to override the default configuration, you can simply extend the configuration as follows:

// eslint.config.js
export { default } from '@slango.configs/eslint/{preset-you-wish-to-use}.js';

Perfectionist rule strictness

Perfectionist sorting rules are organized into tiers and can be configured with four levels of strictness:

| Level | Description | Use Case | | ---------- | -------------------------------------------------- | ---------------------------------------- | | off | All perfectionist rules disabled | When you want no automatic sorting | | relaxed | Import/export sorting only (default) | Universally accepted, industry standard | | moderate | Adds type sorting (interfaces, unions, enums) | Good for type-heavy TypeScript codebases | | strict | Full sorting including objects, classes, JSX props | Maximum consistency, use with caution |

Rule tiers

Tier 1 - Import/Export sorting (relaxed+)

• sort-imports, sort-named-imports, sort-named-exports, sort-exports
• sort-import-attributes, sort-export-attributes, sort-modules

Tier 2 - Type sorting (moderate+)

• sort-union-types, sort-intersection-types, sort-heritage-clauses
• sort-object-types, sort-interfaces, sort-enums

Tier 3 - Full sorting (strict only)

• sort-objects, sort-classes, sort-jsx-props, sort-decorators
• sort-switch-case, sort-variable-declarations, sort-array-includes
• sort-sets, sort-maps

Note: Tier 3 rules are disabled by default because they can be controversial or break intentional ordering. For example, sort-decorators can break functionality when decorator order matters semantically, and sort-switch-case often disrupts intentional case ordering (common cases first, fallbacks last).

To use a custom level, import the corresponding creator and pass an options object:

// eslint.config.js
import { createTypescriptConfig } from '@slango.configs/eslint/typescript.js';

export default createTypescriptConfig({ perfectionist: 'moderate' });

Passing an unknown option or an invalid level throws a descriptive error.

Things to take into account (and possibly review)

• At the time of writing eslint-config-prettier is needed as a dependency to use eslint-plugin-prettier
• eslint-plugin-import-x supports eslint 9 but eslint-plugin-import does not usage comparison
• eslint-import-resolver-node does not seem to play well with monorepo/pattern exports in package.json (thus eslint-import-resolver-typescript is used even for javascript)

Interesting links

• Eslint v9 supported community plugins