Merge pull request #230 from ckeditor/epic/ck/18475-eslint9

Other: The repository now uses ESLint v9. Therefore, the required Node.js version has been upgraded to 22 to match the ESLint requirements.

BREAKING CHANGE: Updated the required version of Node.js to 22.

Author: pomek

.eslintrc.cjs

@@ -0,0 +1,55 @@
+/**
+ * @license Copyright (c) 2020-2025, CKSource Holding sp. z o.o. All rights reserved.
+ * For licensing, see LICENSE.md.
+ */
+
+import globals from 'globals';
+import { defineConfig } from 'eslint/config';
+import eslintConfigCKEditor5 from 'eslint-config-ckeditor5';
+import eslintPluginCKEditor5Rules from 'eslint-plugin-ckeditor5-rules';
+
+export default defineConfig( [
+	eslintConfigCKEditor5,
+	{
+		name: 'Ignored files config',
+		ignores: [
+			'coverage/**'
+		]
+	},
+	{
+		name: 'Base config',
+		languageOptions: {
+			ecmaVersion: 'latest',
+			sourceType: 'module',
+			globals: {
+				...globals.node
+			}
+		},
+		linterOptions: {
+			reportUnusedInlineConfigs: 'error',
+			reportUnusedDisableDirectives: 'error'
+		},
+		plugins: {
+			'ckeditor5-rules': eslintPluginCKEditor5Rules
+		},
+		rules: {
+			'no-console': 'off',
+			'ckeditor5-rules/license-header': [ 'error', { headerLines: [
+				'/**',
+				' * @license Copyright (c) 2020-2025, CKSource Holding sp. z o.o. All rights reserved.',
+				' * For licensing, see LICENSE.md.',
+				' */'
+			] } ],
+			'ckeditor5-rules/require-file-extensions-in-imports': [ 'error', {
+				extensions: [ '.ts', '.js', '.json' ]
+			} ]
+		}
+	},
+	{
+		name: 'Templates config',
+		files: [ './packages/ckeditor5-package-generator/lib/templates/**/*.{js,cjs,ts}' ],
+		rules: {
+			'ckeditor5-rules/license-header': 'off'
+		}
+	}
+] );

eslint.config.js

@@ -18,31 +18,36 @@
   "homepage": "https://ckeditor.com/ckeditor-5",
   "type": "module",
   "devDependencies": {
-    "@ckeditor/ckeditor5-dev-bump-year": "^48.0.0",
-    "@ckeditor/ckeditor5-dev-ci": "^48.0.0",
-    "@ckeditor/ckeditor5-dev-release-tools": "^48.0.0",
-    "@ckeditor/ckeditor5-dev-web-crawler": "^48.0.0",
-    "@vitest/coverage-v8": "^2.1.1",
+    "@ckeditor/ckeditor5-dev-bump-year": "^49.0.0",
+    "@ckeditor/ckeditor5-dev-ci": "^49.0.0",
+    "@ckeditor/ckeditor5-dev-release-tools": "^49.0.0",
+    "@ckeditor/ckeditor5-dev-web-crawler": "^49.0.0",
+    "@vitest/coverage-v8": "^3.0.0",
     "chalk": "^5.0.0",
     "coveralls": "^3.1.1",
-    "eslint": "^7.32.0",
-    "eslint-config-ckeditor5": "^6.0.0",
+    "eslint": "^9.27.0",
+    "eslint-config-ckeditor5": "^10.0.0",
+    "eslint-plugin-ckeditor5-rules": "^10.0.0",
     "fs-extra": "^11.2.0",
     "glob": "^10.2.5",
+    "globals": "^16.1.0",
     "husky": "^8.0.2",
     "lint-staged": "^10.5.4",
     "minimist": "^1.2.8",
     "semver": "^7.0.0",
     "upath": "^2.0.1",
-    "vitest": "^2.1.9"
+    "vitest": "^3.0.0"
+  },
+  "resolutions": {
+    "string-width": "^4.0.0"
   },
   "engines": {
-    "node": ">=20.0.0"
+    "node": ">=22.0.0"
   },
   "scripts": {
     "postinstall": "node ./scripts/postinstall.js",
     "changelog": "node scripts/release/changelog.js",
-    "lint": "eslint --quiet \"**/*.js\"",
+    "lint": "eslint",
     "precommit": "lint-staged",
     "release:prepare-packages": "node scripts/release/preparepackages.js",
     "release:publish-packages": "node scripts/release/publishpackages.js",
@@ -56,14 +61,10 @@
     "url": "https://github.com/ckeditor/ckeditor5-package-generator.git"
   },
   "lint-staged": {
-    "**/*.js": [
-      "eslint --quiet"
+    "**/*": [
+      "eslint"
     ]
   },
-  "eslintIgnore": [
-    "coverage/**",
-    "packages/*/node_modules/**"
-  ],
   "workspaces": {
     "packages": [
       "packages/*"

package.json

@@ -0,0 +1,81 @@
+import globals from 'globals';
+import { defineConfig } from 'eslint/config';
+import eslintConfigCKEditor5 from 'eslint-config-ckeditor5';
+import eslintPluginCKEditor5Rules from 'eslint-plugin-ckeditor5-rules';
+
+export default defineConfig( [
+	eslintConfigCKEditor5,
+	{
+		name: 'Ignored files config',
+		ignores: [
+			// Ignore the entire `dist/`.
+			'dist/**',
+			// Ignore the entire `build/` (the DLL build).
+			'build/**'
+		]
+	},
+	{
+		name: 'Base config',
+		languageOptions: {
+			ecmaVersion: 'latest',
+			sourceType: 'module'
+		},
+		linterOptions: {
+			reportUnusedInlineConfigs: 'error',
+			reportUnusedDisableDirectives: 'error'
+		},
+		plugins: {
+			'ckeditor5-rules': eslintPluginCKEditor5Rules
+		},
+		rules: {
+			//  This rule disallows importing from any path other than the package main entrypoint.
+			'ckeditor5-rules/allow-imports-only-from-main-package-entry-point': 'error',
+			// As required by the ECMAScript (ESM) standard, all imports must include a file extension.
+			// If the import does not include it, this rule will try to automatically detect the correct file extension.
+			'ckeditor5-rules/require-file-extensions-in-imports': [ 'error', {
+				extensions: [ '.ts', '.js', '.json' ]
+			} ],
+			// This rule disallows importing core DLL packages directly. Imports should be done using the `ckeditor5` package.
+			// Also, importing non-DLL packages is not allowed. If the package requires other features to work, they should be
+			// specified as soft-requirements.
+			// Read more: https://ckeditor.com/docs/ckeditor5/latest/builds/guides/migration/migration-to-26.html#soft-requirements.
+			'ckeditor5-rules/ckeditor-imports': 'error'
+		}
+	},
+	{
+		name: 'NodeJS environment config',
+		files: [
+			'./scripts/**/*.{js,mjs,cjs}'
+		],
+		languageOptions: {
+			globals: {
+				...globals.node
+			}
+		}
+	},
+	{
+		name: 'Browser environment config',
+		files: [
+			'./sample/**/*.{js,mjs,cjs}',
+			'./src/**/*.{js,mjs,cjs}',
+			'./tests/**/*.{js,mjs,cjs}'
+		],
+		languageOptions: {
+			globals: {
+				...globals.browser
+			}
+		}
+	},
+	{
+		name: 'Sample and tests config',
+		files: [
+			'sample/**/*.{js,mjs,cjs}',
+			'tests/**/*.{js,mjs,cjs}'
+		],
+		rules: {
+			// To write complex tests, you may need to import files that are not exported in DLL files by default.
+			// Hence, imports CKEditor 5 packages in test files are not checked.
+			'ckeditor5-rules/ckeditor-imports': 'off'
+		}
+	}
+] );

packages/ckeditor5-package-generator/lib/templates/js-legacy/.eslintrc.cjs

@@ -23,10 +23,6 @@
     "./package.json": "./package.json"
   },
   "license": "MIT",
-  "engines": {
-    "node": ">=20.0.0",
-    "npm": ">=5.7.1"
-  },
   "files": [
     "dist",
     "lang",
@@ -37,18 +33,20 @@
   ],
   "devDependencies": {
     "@ckeditor/ckeditor5-dev-build-tools": "<%= packageVersions.ckeditor5DevBuildTools %>",
-    "@ckeditor/ckeditor5-inspector": ">=<%= packageVersions.ckeditor5Inspector %>",
+    "@ckeditor/ckeditor5-inspector": "^<%= packageVersions.ckeditor5Inspector %>",
     "@ckeditor/ckeditor5-package-tools": "<%= packageVersions.packageTools %>",
     "@vitest/coverage-istanbul": "^2.0.5",
     "@vitest/browser": "^2.0.5",
     "ckeditor5": "latest",
-    "eslint": "^7.32.0",
-    "eslint-config-ckeditor5": ">=<%= packageVersions.eslintConfigCkeditor5 %>",
+    "eslint": "^9.27.0",
+    "eslint-config-ckeditor5": "^<%= packageVersions.eslintConfigCkeditor5 %>",
+    "eslint-plugin-ckeditor5-rules": "^<%= packageVersions.eslintPluginCkeditor5Rules %>",
+    "globals": "^16.1.0",
     "http-server": "^14.1.0",
     "husky": "^4.2.5",
     "lint-staged": "^10.2.6",
     "stylelint": "^13.13.1",
-    "stylelint-config-ckeditor5": ">=<%= packageVersions.stylelintConfigCkeditor5 %>",
+    "stylelint-config-ckeditor5": "^<%= packageVersions.stylelintConfigCkeditor5 %>",
     "vite-plugin-svgo": "~1.4.0",
     "vitest": "^2.0.5",
     "webdriverio": "^9.0.7"
@@ -60,7 +58,7 @@
     "build:dist": "node ./scripts/build-dist.mjs",
     "dll:build": "ckeditor5-package-tools dll:build",
     "dll:serve": "http-server ./ -o sample/dll.html",
-    "lint": "eslint \"**/*.js\" --quiet",
+    "lint": "eslint",
     "start": "ckeditor5-package-tools start",
     "stylelint": "stylelint --quiet --allow-empty-input 'theme/**/*.css'",
     "test": "vitest",
@@ -70,8 +68,8 @@
     "translations:validate": "ckeditor5-package-tools translations:synchronize --validate-only"
   },
   "lint-staged": {
-    "**/*.js": [
-      "eslint --quiet"
+    "**/*": [
+      "eslint"
     ],
     "**/*.css": [
       "stylelint --quiet --allow-empty-input"

packages/ckeditor5-package-generator/lib/templates/js-legacy/eslint.config.js

@@ -19,8 +19,6 @@ import { Base64UploadAdapter } from '@ckeditor/ckeditor5-upload';
 
 import <%= formattedNames.plugin.pascalCase %> from '../src/<%= formattedNames.plugin.lowerCaseMerged %>.js';
 
-/* global document, window */
-
 ClassicEditor
 	.create( document.querySelector( '#editor' ), {
 		licenseKey: 'GPL',

packages/ckeditor5-package-generator/lib/templates/js-legacy/package.json

@@ -5,8 +5,6 @@
  * For licensing, see LICENSE.md.
  */
 
-/* eslint-env node */
-
 import { createRequire } from 'module';
 import upath from 'upath';
 import chalk from 'chalk';

packages/ckeditor5-package-generator/lib/templates/js-legacy/sample/ckeditor.js.txt

@@ -5,8 +5,6 @@ import { Heading } from '@ckeditor/ckeditor5-heading';
 import { ClassicEditor } from '@ckeditor/ckeditor5-editor-classic';
 import <%= formattedNames.plugin.pascalCase %> from '../src/<%= formattedNames.plugin.lowerCaseMerged %>.js';
 
-/* global document */
-
 describe( '<%= formattedNames.plugin.pascalCase %>', () => {
 	it( 'should be named', () => {
 		expect( <%= formattedNames.plugin.pascalCase %>.pluginName ).to.equal( '<%= formattedNames.plugin.pascalCase %>' );