eslint-plugin-n

eslint-plugin-n

forked from eslint-plugin-node v11.1.0. as the original repository seems no longer maintained.

Additional ESLint's rules for Node.js

💿 Install & Usage

npm install --save-dev eslint eslint-plugin-n

• Requires Node.js >=16.0.0
• Requires ESLint >=7.0.0

Note: It recommends a use of the "engines" field of package.json. The "engines" field is used by n/no-unsupported-features/* rules.

.eslintrc.json (An example)

{
    "extends": ["eslint:recommended", "plugin:n/recommended"],
    "parserOptions": {
        "ecmaVersion": 2021
    },
    "rules": {
        "n/exports-style": ["error", "module.exports"]
    }
}

eslint.config.js (requires eslint>=v8.23.0)

const nodeRecommendedScript = require("eslint-plugin-n/configs/recommended-script")

module.exports = [
    nodeRecommendedScript,
    {
        rules: {
            "n/exports-style": ["error", "module.exports"]
        }
    }
]

package.json (An example)

{
    "name": "your-module",
    "version": "1.0.0",
    "type": "commonjs",
    "engines": {
        "node": ">=8.10.0"
    }
}

Configured Node.js version range

The rules get the supported Node.js version range from the following, falling back to the next if unspecified:

1. Rule configuration version
2. ESLint shared setting node.version
3. package.json [engines] field
4. >=16.0.0

If you omit the [engines] field, this rule chooses >=16.0.0 as the configured Node.js version since 16 is the maintained lts (see also Node.js Release Working Group).

For Node.js packages, using the [engines] field is recommended because it's the official way to indicate support:

{
    "name": "your-module",
    "version": "1.0.0",
    "engines": {
        "node": ">=16.0.0"
    }
}

For Shareable Configs or packages with a different development environment (e.g. pre-compiled, web package, etc.), you can configure ESLint with settings.node.version to specify support.

📖 Rules

💼 Configurations enabled in.
✅ Set in the recommended configuration.
🔧 Automatically fixable by the --fix CLI option.
❌ Deprecated.

Best Practices

Name	Description	💼	🔧	❌
no-deprecated-api	disallow deprecated APIs	✅

Possible Errors

Name	Description	💼	🔧	❌
handle-callback-err	require error handling in callbacks
no-callback-literal	enforce Node.js-style error-first callback pattern is followed
no-exports-assign	disallow the assignment to exports	✅
no-extraneous-import	disallow import declarations which import extraneous modules	✅
no-extraneous-require	disallow require() expressions which import extraneous modules	✅
no-hide-core-modules	disallow third-party modules which are hiding core modules			❌
no-missing-import	disallow import declarations which import non-existence modules	✅
no-missing-require	disallow require() expressions which import non-existence modules	✅
no-new-require	disallow new operators with calls to require
no-path-concat	disallow string concatenation with __dirname and __filename
no-process-exit	disallow the use of process.exit()	✅
no-unpublished-bin	disallow bin files that npm ignores	✅
no-unpublished-import	disallow import declarations which import private modules	✅
no-unpublished-require	disallow require() expressions which import private modules	✅
no-unsupported-features	disallow unsupported ECMAScript features on the specified version			❌
no-unsupported-features/es-builtins	disallow unsupported ECMAScript built-ins on the specified version	✅
no-unsupported-features/es-syntax	disallow unsupported ECMAScript syntax on the specified version	✅
no-unsupported-features/node-builtins	disallow unsupported Node.js built-in APIs on the specified version	✅
process-exit-as-throw	require that process.exit() expressions use the same code path as throw	✅
shebang	require correct usage of shebang	✅	🔧

Stylistic Issues

Name	Description	💼	🔧	❌
callback-return	require return statements after callbacks
exports-style	enforce either module.exports or exports		🔧
file-extension-in-import	enforce the style of file extensions in import declarations		🔧
global-require	require require() calls to be placed at top-level module scope
no-mixed-requires	disallow require calls to be mixed with regular variable declarations
no-process-env	disallow the use of process.env
no-restricted-import	disallow specified modules when loaded by import declarations
no-restricted-require	disallow specified modules when loaded by require
no-sync	disallow synchronous methods
prefer-global/buffer	enforce either Buffer or require("buffer").Buffer
prefer-global/console	enforce either console or require("console")
prefer-global/process	enforce either process or require("process")
prefer-global/text-decoder	enforce either TextDecoder or require("util").TextDecoder
prefer-global/text-encoder	enforce either TextEncoder or require("util").TextEncoder
prefer-global/url	enforce either URL or require("url").URL
prefer-global/url-search-params	enforce either URLSearchParams or require("url").URLSearchParams
prefer-promises/dns	enforce require("dns").promises
prefer-promises/fs	enforce require("fs").promises

🔧 Configs

This plugin provides three configs:

Name	Description
plugin:n/recommended	Considers both CommonJS and ES Modules. If "type":"module" field existed in package.json then it considers files as ES Modules. Otherwise it considers files as CommonJS. In addition, it considers *.mjs files as ES Modules and *.cjs files as CommonJS.
plugin:n/recommended-module	Considers all files as ES Modules.
plugin:n/recommended-script	Considers all files as CommonJS.

These preset configs:

• enable no-process-exit rule because the official document does not recommend a use of process.exit().
• enable plugin rules which are given ✅ in the above table.
• add {ecmaVersion: 2021} and etc into parserOptions.
• add proper globals into globals.
• add this plugin into plugins.

👫 FAQ

• Q: The no-missing-import / no-missing-require rules don't work with nested folders in SublimeLinter-eslint

• A: See context.getFilename() in rule returns relative path in the SublimeLinter-eslint FAQ.

• Q: How to use the new eslint config with mixed commonjs and es modules?

• A: The recommended config is no longer exported. You can create a config based on recommended-script and recommended-module. An example:

const nodeRecommendedScript = require("eslint-plugin-n/configs/recommended-script");
const nodeRecommendedModule = require("eslint-plugin-n/configs/recommended-module");

module.exports = [
    {
        files: ["**/*.js", "**/*.cjs"],
        ...nodeRecommendedScript
    },
    {
        files: ["**/*.mjs"],
        ...nodeRecommendedModule
    }
]

🚥 Semantic Versioning Policy

eslint-plugin-n follows semantic versioning and ESLint's Semantic Versioning Policy.

• Patch release (intended to not break your lint build)
  • A bug fix in a rule that results in it reporting fewer errors.
  • 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 it reporting more errors.
  • A new rule is created.
  • A new option to an existing rule is created.
  • An existing rule is deprecated.
• Major release (likely to break your lint build)
  • A support for old Node version is dropped.
  • A support for old ESLint version is dropped.
  • An existing rule is changed in it reporting more errors.
  • An existing rule is removed.
  • An existing option of a rule is removed.
  • An existing config is updated.

Deprecated rules follow ESLint's deprecation policy.

📰 Changelog

• GitHub Releases

❤️ Contributing

Welcome contributing!

Please use GitHub's Issues/PRs.

Development Tools

• npm test runs tests and measures coverage.
• npm run coverage shows the coverage result of npm test command.
• npm run clean removes the coverage result of npm test command.