@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• ✅ remove-no-unpublished-require;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

1{
2    "rules": {
3        "eslint/add-putout": "on",
4        "eslint/apply-define-config": "on",
5        "eslint/apply-dir-to-flat": "on",
6        "eslint/apply-create-eslint": "on",
7        "eslint/apply-ignores": ["off", {
8            "ignores": ["**/fixture"]
9        }],
10        "eslint/apply-safe-align": "on",
11        "eslint/apply-match-to-flat": "on",
12        "eslint/declare": "on",
13        "eslint/move-putout-to-end-of-extends": "on",
14        "eslint/convert-export-match-to-decleration": "on",
15        "eslint/convert-files-to-array": "on",
16        "eslint/convert-ide-to-safe": "on",
17        "eslint/convert-require-to-import": "on",
18        "eslint/convert-node-to-n": "on",
19        "eslint/convert-plugins-array-to-object": "on",
20        "eslint/convert-rc-to-flat": "off",
21        "eslint/remove-no-missing": "on",
22        "eslint/remove-no-unpublished-require": "on",
23        "eslint/remove-no-unsupported-features": "on",
24        "eslint/remove-overrides-with-empty-rules": "on",
25        "eslint/remove-useless-slice": "on",
26        "eslint/remove-useless-define-config": "on",
27        "eslint/remove-useless-properties": "on",
28        "eslint/remove-useless-match-to-flat": "on",
29        "eslint/remove-parser-options": "on",
30        "eslint/remove-suffix-config": "on",
31        "eslint/remove-create-eslint-config-with-one-argument": "on",
32        "eslint/remove-spread-from-create-eslint-config": "on"
33    }
34}

add-putout

1{
2    "extends": [
3+       "plugin:putout/safe+align",
4        "plugin:node/recommended"
5    ],
6    "plugins": [
7+       "putout",
8        "node"
9    ]
10}

apply-define-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1import {safeAlign} from 'eslint-plugin-putout';
2import {createESLintConfig} from '@putout/eslint-flat';
3
4export default createESLintConfig([
5    safeAlign, {
6        ignores: ['**/fixture'],
7    },
8]);

✅ Example of correct code

1import {safeAlign} from 'eslint-plugin-putout';
2import {defineConfig} from '@eslint/config';
3
4export default defineConfig([
5    safeAlign, {
6        ignores: ['**/fixture'],
7    },
8]);

apply-ignores

Checkout in 🐊Putout Editor. Legacy config:

1{
2    "extends": [
3        "plugin:putout/safe+align",
4        "plugin:node/recommended"
5    ],
6    "plugins": [
7        "putout",
8        "node"
9    ],
10    "ignorePatterns": [
11        "**/fixture"
12    ]
13}

Flat config:

1-export default safeAlign;
2+export default [
3+   ...safeAlign, {
4+   ignores: [
5+       "**/fixture"
6+   ]
7+}];

apply-create-eslint

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1export default [
2    ...safeAlign, {
3        ignores: ['**/fixture'],
4    },
5];

✅ Example of correct code

1export default createESLintConfig([
2    safeAlign, {
3        ignores: ['**/fixture'],
4    },
5]);

apply-safe-align

1{
2-    "rules": {
3-       "putout/align-spaces": "error"
4-    },
5    "extends": [
6-       "plugin:putout/safe",
7+       "plugin:putout/safe+align",
8        "plugin:node/recommended"
9    ],
10    "plugins": [
11        "putout",
12        "node"
13    ]
14}

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

1const scriptsConfig = await matchToFlatDir('scripts');
2const monoConfig = await mergeESLintConfigs(['codemods', 'packages', 'rules']);
3
4module.exports = [
5    ...scriptsConfig,
6    ...monoConfig,
7];

✅ Example of correct code

1// CommonJS
2const scriptsConfig = await matchToFlatDir(__dirname, 'scripts');
3
4// ESM
5const monoConfig = await mergeESLintConfigs(import.meta.url, ['codemods', 'packages', 'rules']);
6
7module.exports = [
8    ...scriptsConfig,
9    ...monoConfig,
10];

apply-match-to-flat

Check out in 🐊Putout Editor.

❌ Example of incorrect code

1import {safeAlign} from 'eslint-plugin-putout/config';
2
3export default [
4    ...safeAlign, {
5        files: ['*.d.ts'],
6        rules: {
7            'no-var': 'off',
8        },
9    }, {
10        files: ['*.spec.*'],
11        rules: {
12            'node/no-extraneous-import': 'off',
13        },
14    },
15];

✅ Example of correct code

1import {safeAlign} from 'eslint-plugin-putout/config';
2
3const config = matchToFlat({
4    '*.d.ts': {
5        'no-var': 'off',
6    },
7    '*.spec.*': {
8        'node/no-extraneous-import': 'off',
9    },
10});
11
12export default [
13    ...safeAlign,
14    ...config,
15];

move-putout-to-end-of-extends

❌ Example of incorrect code

1{
2    "extends": [
3        "plugin:putout/recommended",
4        "plugin:node/recommended"
5    ],
6    "plugins": [
7        "putout",
8        "node"
9    ]
10}

✅ Example of correct code

1{
2    "extends": [
3        "plugin:node/recommended",
4        "plugin:putout/recommended"
5    ],
6    "plugins": [
7        "putout",
8        "node"
9    ]
10}

convert-ide-to-safe

❌ Example of incorrect code

1{
2    "extends": [
3        "plugin:node/recommended",
4        "plugin:putout/ide"
5    ],
6    "plugins": [
7        "putout",
8        "node"
9    ]
10}

✅ Example of correct code

1{
2    "extends": [
3        "plugin:node/recommended",
4        "plugin:putout/safe"
5    ],
6    "plugins": [
7        "putout",
8        "node"
9    ]
10}

convert-files-to-array

Check it out in 🐊Putout Editor.

1{
2    "overrides": [{
3-        "files": "test/*.js",
4+        "files": ["test/*.js"],
5         "rules": {
6           "node/no-missing-require": "off"
7        }
8    }],
9};

convert-require-to-import

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

1{
2    "overrides": [{
3        "files": "test/*.js",
4        "rules": {
5-           "node/no-missing-require": "off"
6+           "node/no-missing-import": "off"
7        }
8    }],
9    "extends": [
10        "plugin:node/recommended",
11        "plugin:putout/recommended"
12    ],
13    "plugins": [
14        "putout",
15        "node"
16    ]
17};

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.

1{
2    "overrides": [{
3        "files": "test/*.js",
4        "rules": {
5-           "node/no-unpublished-require": "off"
6        }
7    }],
8    "extends": [
9        "plugin:node/recommended",
10        "plugin:putout/recommended"
11    ],
12    "plugins": [
13        "putout",
14        "node"
15    ]
16};

remove-no-unsupported-features

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

1{
2    "overrides": [{
3        "files": "test/*.js",
4        "rules": {
5-           "node/no-unpublished-require": "off"
6        }
7    }],
8    "extends": [
9        "plugin:node/recommended",
10        "plugin:putout/recommended"
11    ],
12    "plugins": [
13        "putout",
14        "node"
15    ]
16};

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:

1{
2-   "overrides": [{
3-       "files": "test/*.js",
4-       "rules": {
5-       }
6-   }],
7    "extends": [
8        "plugin:node/recommended",
9        "plugin:putout/recommended"
10    ],
11    "plugins": [
12        "putout",
13        "node"
14    ]
15};

Or remove empty overrides:

1{
2-   "overrides": [],
3    "extends": [
4        "plugin:node/recommended",
5        "plugin:putout/recommended"
6    ],
7    "plugins": [
8        "putout",
9        "node"
10    ]
11};

And ofcourse remove only elements with empty rules:

1{
2  "overrides": [{
3-   "files": "test/*.js",
4-   "rules": {
5-   }
6- }, {
7    "files": "test/*.js",
8    "rules": {
9      "no-semi": "off"
10    }
11  }],
12    "extends": [
13      "plugin:node/recommended",
14      "plugin:putout/recommended"
15    ],
16    "plugins": [
17      "putout",
18      "node"
19    ]
20};

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

1const ruleTester = new RuleTester({
2    languageOptions: {
3        parserOptions: {
4            ecmaVersion: 2025,
5            sourceType: 'module',
6        },
7    },
8});

✅ Example of correct code

1const ruleTester = new RuleTester({
2    languageOptions: {
3        ecmaVersion: 2025,
4        sourceType: 'module',
5    },
6});

remove-suffix-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1import {safeAlign} from 'eslint-plugin-putout/config';

✅ Example of correct code

1import {safeAlign} from 'eslint-plugin-putout';

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

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1export default createESLintConfig([safeAlign]);

✅ Example of correct code

1export default safeAlign;

remove-spread-from-create-eslint-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1export default createESLintConfig([
2    safeAlign,
3    ...matchToFlat(match),
4]);

✅ Example of correct code

1export default createESLintConfig([safeAlign, matchToFlat(match)]);

convert-node-to-n

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

1{
2    "extends": [
3        "plugin:putout/safe+align",
4-       "plugin:node/recommended"
5+       "plugin:n/recommended"
6    ],
7    "plugins": [
8        "putout",
9-       "node"
10+       "n"
11    ]
12}

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.

1{
2    "overrides": [{
3        "files": "test/*.js",
4        "rules": {
5-           "node/no-missing-require": "off",
6-           "node/no-missing-import": "off"
7        }
8    }],
9    "extends": [
10        "plugin:node/recommended",
11        "plugin:putout/recommended"
12    ],
13    "plugins": [
14        "putout",
15        "node"
16    ]
17};

remove-useless-slice

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

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1export default x.slice();
2
3module.exports = x.slice();

✅ Example of correct code

1export default x;
2
3module.exports = x;

remove-useless-define-config

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1export default defineConfig([safeAlign]);

✅ Example of correct code

1export default safeAlign;

remove-useless-properties

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1module.exports = [
2    ...safeAlign, {
3        rules: {},
4    },
5];

✅ Example of correct code

1module.exports = safeAlign;

remove-useless-match-to-flat

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

1import {safeAlign} from 'eslint-plugin-putout';
2
3export let match;
4export default createESLintConfig([safeAlign, matchToFlat(match)]);

✅ Example of correct code

1import {safeAlign} from 'eslint-plugin-putout';
2
3export default safeAlign;

convert-export-match-to-declaration

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

❌ Example of incorrect code

1module.exports.match = {
2    'bin/**': {
3        'no-process-exit': 'off',
4    },
5};
6
7module.exports = [
8    ...safeAlign, {
9        rules: {
10            'node/no-unsupported-features/node-builtins': 'off',
11        },
12    },
13    ...matchToFlat(match),
14];

✅ Example of correct code

1const match = {
2    'bin/**': {
3        'no-process-exit': 'off',
4    },
5};
6
7module.exports = [
8    ...safeAlign, {
9        rules: {
10            'node/no-unsupported-features/node-builtins': 'off',
11        },
12    },
13    ...matchToFlat(match),
14];
15
16module.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

1import {types} from 'putout';
2
3const {react} = types;
4
5export default {
6    plugins: [react],
7};
8
9module.exports = {
10    plugins: ['react'],
11};

✅ Example of correct code

1import {types} from 'putout';
2
3const {react} = types;
4
5export default {
6    plugins: {
7        react,
8    },
9};
10
11module.exports = {
12    plugins: ['react'],
13};

convert-rc-to-flat

Checkout in 🐊Putout Editor:

• Scanner;
• Traverser;

Converts .eslintrc.json:

1{
2    "root": true,
3    "parser": "@typescript-eslint/parser",
4    "env": {
5        "node": true
6    },
7    "extends": ["eslint:recommended"],
8    "plugins": ["@nx"],
9    "rules": {
10        "@typescript-eslint/explicit-module-boundary-types": "error"
11    },
12    "overrides": [{
13        "files": ["*.json"],
14        "parser": "jsonc-eslint-parser"
15    }, {
16        "files": [
17            "*.ts",
18            "*.tsx",
19            "*.js",
20            "*.jsx"
21        ],
22        "rules": {
23            "@nx/enforce-module-boundaries": ["error", {
24                "enforceBuildableLibDependency": true,
25                "allow": [],
26                "depConstraints": [{
27                    "sourceTag": "*",
28                    "onlyDependOnLibsWithTags": ["*"]
29                }]
30            }]
31        }
32    }]
33}

To .eslint.config.js:

1const nxPlugin = require('@nx/eslint-plugin');
2const js = require('@eslint/js');
3const globals = require('globals');
4const jsoncParser = require('jsonc-eslint-parser');
5const tsParser = require('@typescript-eslint/parser');
6
7module.exports = [
8    js.configs.recommended, {
9        plugins: {
10            '@nx': nxPlugin,
11        },
12    }, {
13        languageOptions: {
14            parser: tsParser,
15            globals: {
16                ...globals.node,
17            },
18        },
19        rules: {
20            '@typescript-eslint/explicit-module-boundary-types': ['error'],
21        },
22    }, {
23        files: ['*.json'],
24        languageOptions: {
25            parser: jsoncParser,
26        },
27        rules: {},
28    }, {
29        files: [
30            '*.ts',
31            '*.tsx',
32            '*.js',
33            '*.jsx',
34        ],
35        rules: {
36            '@nx/enforce-module-boundaries': ['error', {
37                enforceBuildableLibDependency: true,
38                allow: [],
39                depConstraints: [{
40                    sourceTag: '*',
41                    onlyDependOnLibsWithTags: ['*'],
42                }],
43            }],
44        },
45    }];

License

MIT