plugin-eslint

@putout/plugin-eslint

Find and fix problems in your JavaScript code

(c) eslint.org

🐊Putout plugin helps to automate fixing ESLint config.

Install

npm i @putout/plugin-eslint -D

Rules

• ✅ add-putout;
• ✅ apply-define-config;
• ✅ apply-dir-to-flat;
• ✅ apply-ignores;
• ✅ apply-create-eslint;
• ✅ apply-match-to-flat;
• ✅ apply-safe-align;
• ✅ convert-export-match-to-declaration;
• ✅ convert-files-to-array;
• ✅ convert-ide-to-safe;
• ✅ convert-node-to-n;
• ✅ convert-plugins-array-to-object;
• ✅ convert-rc-to-flat;
• ✅ convert-require-to-import;
• ✅ declare;
• ✅ move-putout-to-end-of-extends;
• ✅ remove-no-missing;
• ✅ remove-useless-define-config;
• ✅ remove-no-unpublished-require;
• ✅ remove-no-unsupported-features;
• ✅ remove-overrides-with-empty-rules;
• ✅ remove-useless-slice;
• ✅ remove-useless-properties;
• ✅ remove-useless-match-to-flat;
• ✅ remove-parser-options;
• ✅ remove-suffix-config;
• ✅ remove-create-eslint-config-with-one-argument;
• ✅ remove-spread-from-create-eslint-config;

Config

{
    "rules": {
        "eslint/add-putout": "on",
        "eslint/apply-define-config": "on",
        "eslint/apply-dir-to-flat": "on",
        "eslint/apply-create-eslint": "on",
        "eslint/apply-ignores": ["off", {
            "ignores": ["**/fixture"]
        }],
        "eslint/apply-safe-align": "on",
        "eslint/apply-match-to-flat": "on",
        "eslint/declare": "on",
        "eslint/move-putout-to-end-of-extends": "on",
        "eslint/convert-export-match-to-decleration": "on",
        "eslint/convert-files-to-array": "on",
        "eslint/convert-ide-to-safe": "on",
        "eslint/convert-require-to-import": "on",
        "eslint/convert-node-to-n": "on",
        "eslint/convert-plugins-array-to-object": "on",
        "eslint/convert-rc-to-flat": "off",
        "eslint/remove-no-missing": "on",
        "eslint/remove-no-unpublished-require": "on",
        "eslint/remove-no-unsupported-features": "on",
        "eslint/remove-overrides-with-empty-rules": "on",
        "eslint/remove-useless-slice": "on",
        "eslint/remove-useless-define-config": "on",
        "eslint/remove-useless-properties": "on",
        "eslint/remove-useless-match-to-flat": "on",
        "eslint/remove-parser-options": "on",
        "eslint/remove-suffix-config": "on",
        "eslint/remove-create-eslint-config-with-one-argument": "on",
        "eslint/remove-spread-from-create-eslint-config": "on"
    }
}

add-putout

{
    "extends": [
+       "plugin:putout/safe+align",
        "plugin:node/recommended"
    ],
    "plugins": [
+       "putout",
        "node"
    ]
}

apply-define-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import {safeAlign} from 'eslint-plugin-putout';
import {createESLintConfig} from '@putout/eslint-flat';

export default createESLintConfig([
    safeAlign, {
        ignores: ['**/fixture'],
    },
]);

✅ Example of correct code

import {safeAlign} from 'eslint-plugin-putout';
import {defineConfig} from '@eslint/config';

export default defineConfig([
    safeAlign, {
        ignores: ['**/fixture'],
    },
]);

apply-ignores

Checkout in 🐊Putout Editor. Legacy config:

{
    "extends": [
        "plugin:putout/safe+align",
        "plugin:node/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ],
    "ignorePatterns": [
        "**/fixture"
    ]
}

Flat config:

-export default safeAlign;
+export default [
+   ...safeAlign, {
+   ignores: [
+       "**/fixture"
+   ]
+}];

apply-create-eslint

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

export default [
    ...safeAlign, {
        ignores: ['**/fixture'],
    },
];

✅ Example of correct code

export default createESLintConfig([
    safeAlign, {
        ignores: ['**/fixture'],
    },
]);

apply-safe-align

{
-    "rules": {
-       "putout/align-spaces": "error"
-    },
    "extends": [
-       "plugin:putout/safe",
+       "plugin:putout/safe+align",
        "plugin:node/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
}

apply-dir-to-flat

matchToFlatDir() and mergeESLintConfigs supports __dirname or import.meta.url starting from v2 of @putout/eslint-flat.

Check out in 🐊Putout Editor.

❌ Example of incorrect code

const scriptsConfig = await matchToFlatDir('scripts');
const monoConfig = await mergeESLintConfigs(['codemods', 'packages', 'rules']);

module.exports = [
    ...scriptsConfig,
    ...monoConfig,
];

✅ Example of correct code

// CommonJS
const scriptsConfig = await matchToFlatDir(__dirname, 'scripts');

// ESM
const monoConfig = await mergeESLintConfigs(import.meta.url, ['codemods', 'packages', 'rules']);

module.exports = [
    ...scriptsConfig,
    ...monoConfig,
];

apply-match-to-flat

Check out in 🐊Putout Editor.

❌ Example of incorrect code

import {safeAlign} from 'eslint-plugin-putout/config';

export default [
    ...safeAlign, {
        files: ['*.d.ts'],
        rules: {
            'no-var': 'off',
        },
    }, {
        files: ['*.spec.*'],
        rules: {
            'node/no-extraneous-import': 'off',
        },
    },
];

✅ Example of correct code

import {safeAlign} from 'eslint-plugin-putout/config';

const config = matchToFlat({
    '*.d.ts': {
        'no-var': 'off',
    },
    '*.spec.*': {
        'node/no-extraneous-import': 'off',
    },
});

export default [
    ...safeAlign,
    ...config,
];

move-putout-to-end-of-extends

❌ Example of incorrect code

{
    "extends": [
        "plugin:putout/recommended",
        "plugin:node/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
}

✅ Example of correct code

{
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
}

convert-ide-to-safe

❌ Example of incorrect code

{
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/ide"
    ],
    "plugins": [
        "putout",
        "node"
    ]
}

✅ Example of correct code

{
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/safe"
    ],
    "plugins": [
        "putout",
        "node"
    ]
}

convert-files-to-array

Check it out in 🐊Putout Editor.

{
    "overrides": [{
-        "files": "test/*.js",
+        "files": ["test/*.js"],
         "rules": {
           "node/no-missing-require": "off"
        }
    }],
};

convert-require-to-import

node/no-missing-require has no sense when type=module in package.json. Check it out in 🐊Putout Editor.

{
    "overrides": [{
        "files": "test/*.js",
        "rules": {
-           "node/no-missing-require": "off"
+           "node/no-missing-import": "off"
        }
    }],
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
};

remove-no-unpublished-require

node/remove-no-unpublished-require should be enabled, since this is a very useful rule, which shows what files should be add to .npmignore.

{
    "overrides": [{
        "files": "test/*.js",
        "rules": {
-           "node/no-unpublished-require": "off"
        }
    }],
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
};

remove-no-unsupported-features

node/remove-no-unsupported-features is already disabled in eslint-plugin-putout.

{
    "overrides": [{
        "files": "test/*.js",
        "rules": {
-           "node/no-unpublished-require": "off"
        }
    }],
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
};

remove-overrides-with-empty-rules

overrides with rules: {} has no sense. Check out in 🐊Putout Editor:

• remove empty rules;
• remove empty overrides;

Remove overrides with one element with empty rules:

{
-   "overrides": [{
-       "files": "test/*.js",
-       "rules": {
-       }
-   }],
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
};

Or remove empty overrides:

{
-   "overrides": [],
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
};

And ofcourse remove only elements with empty rules:

{
  "overrides": [{
-   "files": "test/*.js",
-   "rules": {
-   }
- }, {
    "files": "test/*.js",
    "rules": {
      "no-semi": "off"
    }
  }],
    "extends": [
      "plugin:node/recommended",
      "plugin:putout/recommended"
    ],
    "plugins": [
      "putout",
      "node"
    ]
};

remove-parser-options

In flat config files, the globals, and parserOptions are consolidated under the languageOptions key;

(c) eslint.org

Check out in 🐊Putout Editor

❌ Example of incorrect code

const ruleTester = new RuleTester({
    languageOptions: {
        parserOptions: {
            ecmaVersion: 2025,
            sourceType: 'module',
        },
    },
});

✅ Example of correct code

const ruleTester = new RuleTester({
    languageOptions: {
        ecmaVersion: 2025,
        sourceType: 'module',
    },
});

remove-suffix-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import {safeAlign} from 'eslint-plugin-putout/config';

✅ Example of correct code

import {safeAlign} from 'eslint-plugin-putout';

remove-create-eslint-config-with-one-argument

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

export default createESLintConfig([safeAlign]);

✅ Example of correct code

export default safeAlign;

remove-spread-from-create-eslint-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

export default createESLintConfig([
    safeAlign,
    ...matchToFlat(match),
]);

✅ Example of correct code

export default createESLintConfig([safeAlign, matchToFlat(match)]);

convert-node-to-n

eslint-plugin-node is no longer supported. Better to use eslint-plugin-n.

{
    "extends": [
        "plugin:putout/safe+align",
-       "plugin:node/recommended"
+       "plugin:n/recommended"
    ],
    "plugins": [
        "putout",
-       "node"
+       "n"
    ]
}

remove-no-missing

node/remove-no-missing-require and node/remove-no-missing-import doesn't supports exports and already disabled by eslint-plugin-putout.

{
    "overrides": [{
        "files": "test/*.js",
        "rules": {
-           "node/no-missing-require": "off",
-           "node/no-missing-import": "off"
        }
    }],
    "extends": [
        "plugin:node/recommended",
        "plugin:putout/recommended"
    ],
    "plugins": [
        "putout",
        "node"
    ]
};

remove-useless-slice

Fixes code after convert-array-copy-to-slice.

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

export default x.slice();

module.exports = x.slice();

✅ Example of correct code

export default x;

module.exports = x;

remove-useless-define-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

export default defineConfig([safeAlign]);

✅ Example of correct code

export default safeAlign;

remove-useless-properties

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

module.exports = [
    ...safeAlign, {
        rules: {},
    },
];

✅ Example of correct code

module.exports = safeAlign;

remove-useless-match-to-flat

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import {safeAlign} from 'eslint-plugin-putout';

export let match;
export default createESLintConfig([safeAlign, matchToFlat(match)]);

✅ Example of correct code

import {safeAlign} from 'eslint-plugin-putout';

export default safeAlign;

convert-export-match-to-declaration

Fixes apply-match-to-flat. Checkout in 🐊Putout Editor.

❌ Example of incorrect code

module.exports.match = {
    'bin/**': {
        'no-process-exit': 'off',
    },
};

module.exports = [
    ...safeAlign, {
        rules: {
            'node/no-unsupported-features/node-builtins': 'off',
        },
    },
    ...matchToFlat(match),
];

✅ Example of correct code

const match = {
    'bin/**': {
        'no-process-exit': 'off',
    },
};

module.exports = [
    ...safeAlign, {
        rules: {
            'node/no-unsupported-features/node-builtins': 'off',
        },
    },
    ...matchToFlat(match),
];

module.exports.match = match;

declare

Declare:

• safeAlign;

convert-plugins-array-to-object

On the surface, using a plugin in flat config looks very similar to using a plugin in eslintrc. The big difference is that eslintrc used strings whereas flat configs uses objects. Instead of specifying the name of a plugin, you import the plugin directly and place it into the plugins key.

(c) eslint.org

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

import {types} from 'putout';

const {react} = types;

export default {
    plugins: [react],
};

module.exports = {
    plugins: ['react'],
};

✅ Example of correct code

import {types} from 'putout';

const {react} = types;

export default {
    plugins: {
        react,
    },
};

module.exports = {
    plugins: ['react'],
};

convert-rc-to-flat

Checkout in 🐊Putout Editor:

• Scanner;
• Traverser;

Converts .eslintrc.json:

{
    "root": true,
    "parser": "@typescript-eslint/parser",
    "env": {
        "node": true
    },
    "extends": ["eslint:recommended"],
    "plugins": ["@nx"],
    "rules": {
        "@typescript-eslint/explicit-module-boundary-types": "error"
    },
    "overrides": [{
        "files": ["*.json"],
        "parser": "jsonc-eslint-parser"
    }, {
        "files": [
            "*.ts",
            "*.tsx",
            "*.js",
            "*.jsx"
        ],
        "rules": {
            "@nx/enforce-module-boundaries": ["error", {
                "enforceBuildableLibDependency": true,
                "allow": [],
                "depConstraints": [{
                    "sourceTag": "*",
                    "onlyDependOnLibsWithTags": ["*"]
                }]
            }]
        }
    }]
}

To .eslint.config.js:

const nxPlugin = require('@nx/eslint-plugin');
const js = require('@eslint/js');
const globals = require('globals');
const jsoncParser = require('jsonc-eslint-parser');
const tsParser = require('@typescript-eslint/parser');

module.exports = [
    js.configs.recommended, {
        plugins: {
            '@nx': nxPlugin,
        },
    }, {
        languageOptions: {
            parser: tsParser,
            globals: {
                ...globals.node,
            },
        },
        rules: {
            '@typescript-eslint/explicit-module-boundary-types': ['error'],
        },
    }, {
        files: ['*.json'],
        languageOptions: {
            parser: jsoncParser,
        },
        rules: {},
    }, {
        files: [
            '*.ts',
            '*.tsx',
            '*.js',
            '*.jsx',
        ],
        rules: {
            '@nx/enforce-module-boundaries': ['error', {
                enforceBuildableLibDependency: true,
                allow: [],
                depConstraints: [{
                    sourceTag: '*',
                    onlyDependOnLibsWithTags: ['*'],
                }],
            }],
        },
    }];

License

MIT