# eslint-plugin-node

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Additional ESLint's rules for Node.js

## 💿 Install & Usage

```
$ npm install --save-dev eslint eslint-plugin-node
```

- Requires Node.js `>=8.10.0`
- Requires ESLint `>=5.16.0`

**Note:** It recommends a use of [the "engines" field of package.json](https://docs.npmjs.com/files/package.json#engines). The "engines" field is used by `node/no-unsupported-features/*` rules.

**.eslintrc.json** (An example)

```jsonc
{
    "extends": [
        "eslint:recommended",
        "plugin:node/recommended"
    ],
    "parserOptions": {
        // Only ESLint 6.2.0 and later support ES2020.
        "ecmaVersion": 2020
    },
    "rules": {
        "node/exports-style": ["error", "module.exports"],
        "node/file-extension-in-import": ["error", "always"],
        "node/prefer-global/buffer": ["error", "always"],
        "node/prefer-global/console": ["error", "always"],
        "node/prefer-global/process": ["error", "always"],
        "node/prefer-global/url-search-params": ["error", "always"],
        "node/prefer-global/url": ["error", "always"],
        "node/prefer-promises/dns": "error",
        "node/prefer-promises/fs": "error"
    }
}
```

**package.json** (An example)

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

## 📖 Rules

- ⭐️ - the mark of recommended rules.
- ✒️ - the mark of fixable rules.

<!--RULES_TABLE_START-->
### Possible Errors

| Rule ID | Description |    |
|:--------|:------------|:--:|
| [node/no-callback-literal](./docs/rules/no-callback-literal.md) | ensure Node.js-style error-first callback pattern is followed |  |
| [node/no-exports-assign](./docs/rules/no-exports-assign.md) | disallow the assignment to `exports` | ⭐️ |
| [node/no-extraneous-import](./docs/rules/no-extraneous-import.md) | disallow `import` declarations which import extraneous modules | ⭐️ |
| [node/no-extraneous-require](./docs/rules/no-extraneous-require.md) | disallow `require()` expressions which import extraneous modules | ⭐️ |
| [node/no-missing-import](./docs/rules/no-missing-import.md) | disallow `import` declarations which import non-existence modules | ⭐️ |
| [node/no-missing-require](./docs/rules/no-missing-require.md) | disallow `require()` expressions which import non-existence modules | ⭐️ |
| [node/no-unpublished-bin](./docs/rules/no-unpublished-bin.md) | disallow `bin` files that npm ignores | ⭐️ |
| [node/no-unpublished-import](./docs/rules/no-unpublished-import.md) | disallow `import` declarations which import private modules | ⭐️ |
| [node/no-unpublished-require](./docs/rules/no-unpublished-require.md) | disallow `require()` expressions which import private modules | ⭐️ |
| [node/no-unsupported-features/es-builtins](./docs/rules/no-unsupported-features/es-builtins.md) | disallow unsupported ECMAScript built-ins on the specified version | ⭐️ |
| [node/no-unsupported-features/es-syntax](./docs/rules/no-unsupported-features/es-syntax.md) | disallow unsupported ECMAScript syntax on the specified version | ⭐️ |
| [node/no-unsupported-features/node-builtins](./docs/rules/no-unsupported-features/node-builtins.md) | disallow unsupported Node.js built-in APIs on the specified version | ⭐️ |
| [node/process-exit-as-throw](./docs/rules/process-exit-as-throw.md) | make `process.exit()` expressions the same code path as `throw` | ⭐️ |
| [node/shebang](./docs/rules/shebang.md) | suggest correct usage of shebang | ⭐️✒️ |

### Best Practices

| Rule ID | Description |    |
|:--------|:------------|:--:|
| [node/no-deprecated-api](./docs/rules/no-deprecated-api.md) | disallow deprecated APIs | ⭐️ |

### Stylistic Issues

| Rule ID | Description |    |
|:--------|:------------|:--:|
| [node/exports-style](./docs/rules/exports-style.md) | enforce either `module.exports` or `exports` |  |
| [node/file-extension-in-import](./docs/rules/file-extension-in-import.md) | enforce the style of file extensions in `import` declarations | ✒️ |
| [node/prefer-global/buffer](./docs/rules/prefer-global/buffer.md) | enforce either `Buffer` or `require("buffer").Buffer` |  |
| [node/prefer-global/console](./docs/rules/prefer-global/console.md) | enforce either `console` or `require("console")` |  |
| [node/prefer-global/process](./docs/rules/prefer-global/process.md) | enforce either `process` or `require("process")` |  |
| [node/prefer-global/text-decoder](./docs/rules/prefer-global/text-decoder.md) | enforce either `TextDecoder` or `require("util").TextDecoder` |  |
| [node/prefer-global/text-encoder](./docs/rules/prefer-global/text-encoder.md) | enforce either `TextEncoder` or `require("util").TextEncoder` |  |
| [node/prefer-global/url-search-params](./docs/rules/prefer-global/url-search-params.md) | enforce either `URLSearchParams` or `require("url").URLSearchParams` |  |
| [node/prefer-global/url](./docs/rules/prefer-global/url.md) | enforce either `URL` or `require("url").URL` |  |
| [node/prefer-promises/dns](./docs/rules/prefer-promises/dns.md) | enforce `require("dns").promises` |  |
| [node/prefer-promises/fs](./docs/rules/prefer-promises/fs.md) | enforce `require("fs").promises` |  |

### Deprecated rules

These rules have been deprecated in accordance with the [deprecation policy](https://eslint.org/docs/user-guide/rule-deprecation), and replaced by newer rules:

| Rule ID | Replaced by |
|:--------|:------------|
| [node/no-hide-core-modules](./docs/rules/no-hide-core-modules.md) | (nothing) |
| [node/no-unsupported-features](./docs/rules/no-unsupported-features.md) | [node/node/no-unsupported-features/es-syntax](./docs/rules/node/no-unsupported-features/es-syntax.md) and [node/node/no-unsupported-features/es-builtins](./docs/rules/node/no-unsupported-features/es-builtins.md) |

<!--RULES_TABLE_END-->

## 🔧 Configs

This plugin provides three configs:

- `plugin:node/recommended` condiders both CommonJS and ES Modules. If [`"type":"module"` field](https://medium.com/@nodejs/announcing-a-new-experimental-modules-1be8d2d6c2ff#b023) 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:node/recommended-module` considers all files as ES Modules.
- `plugin:node/recommended-script` considers all files as CommonJS.

Those preset config:

- enable [no-process-exit](http://eslint.org/docs/rules/no-process-exit) rule because [the official document](https://nodejs.org/api/process.html#process_process_exit_code) does not recommend a use of `process.exit()`.
- enable plugin rules which are given :star: in the above table.
- add `{ecmaVersion: 2019}` 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](https://github.com/roadhump/SublimeLinter-eslint#contextgetfilename-in-rule-returns-relative-path) in the SublimeLinter-eslint FAQ.

## 🚥 Semantic Versioning Policy

`eslint-plugin-node` follows [semantic versioning](http://semver.org/) and [ESLint's Semantic Versioning Policy](https://github.com/eslint/eslint#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.

## 📰 Changelog

- [GitHub Releases](https://github.com/mysticatea/eslint-plugin-node/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.