Build: Update ESLint to v9, migrate to flat config, lint dist files

Dist files linting is limited to checking if they're proper ES5.

Closes gh-2336

Author: mgol

.eslintignore

@@ -49,12 +49,13 @@ jobs:
       - name: Install npm dependencies
         run: npm install
 
-      - name: Lint
-        run: npm run lint
-
       - name: Build
         run: npm run build
 
+      # Lint must happen after build as we lint generated files.
+      - name: Lint
+        run: npm run lint
+
       - name: Test
         run: |
           npm run test:unit -- \

.eslintrc.json

@@ -204,9 +204,12 @@ grunt.initConfig( {
 			"ui/**/*.js",
 			"!ui/vendor/**/*.js",
 			"Gruntfile.js",
+			"dist/jquery-ui.js",
+			"dist/jquery-ui.min.js",
 			"build/**/*.js",
 			"tests/unit/**/*.js",
 			"tests/lib/**/*.js",
+			"!tests/lib/vendor/**/*.js",
 			"demos/**/*.js"
 		]
 	},
@@ -401,7 +404,7 @@ grunt.registerTask( "lint", [
 	"htmllint"
 ] );
 grunt.registerTask( "build", [ "requirejs", "concat", "minify:main" ] );
-grunt.registerTask( "default", [ "lint", "build" ] );
+grunt.registerTask( "default", [ "build", "lint" ] );
 grunt.registerTask( "sizer", [ "requirejs:js", "minify:main", "compare_size:all" ] );
 grunt.registerTask( "sizer_all", [ "requirejs:js", "minify", "compare_size" ] );
 

.github/workflows/node.js.yml

@@ -0,0 +1,162 @@
+import jqueryConfig from "eslint-config-jquery";
+import globals from "globals";
+
+export default [
+	{
+		ignores: [
+			"dist/**/*",
+			"!dist/jquery-ui.js",
+			"!dist/jquery-ui.min.js",
+			"external/**/*",
+			"tests/lib/vendor/**/*",
+			"ui/vendor/**/*"
+		]
+	},
+
+	{
+		ignores: [ "dist/**/*" ],
+		rules: {
+			...jqueryConfig.rules,
+			"no-unused-vars": [
+				"error",
+				{
+					argsIgnorePattern: "^_",
+					caughtErrorsIgnorePattern: "^_"
+				}
+			]
+		}
+	},
+
+	{
+		files: [ "Gruntfile.js" ],
+		languageOptions: {
+			ecmaVersion: "latest",
+			sourceType: "commonjs",
+			globals: {
+				...globals.node
+			}
+		},
+		rules: {
+			strict: [ "error", "global" ]
+		}
+	},
+
+	{
+		files: [ "eslint.config.mjs" ],
+		languageOptions: {
+			ecmaVersion: "latest",
+			sourceType: "module",
+			globals: {
+				...globals.node
+			}
+		},
+		rules: {
+			strict: [ "error", "global" ]
+		}
+	},
+
+	// Source, demos
+	{
+		files: [ "ui/**/*.js", "demos/**/*.js" ],
+		languageOptions: {
+			ecmaVersion: 5,
+			sourceType: "script",
+			globals: {
+				...globals.browser,
+				...globals.jquery,
+				define: false,
+				Globalize: false
+			}
+		},
+		rules: {
+			strict: [ "error", "function" ],
+
+			// The following rule is relaxed due to too many violations:
+			"no-unused-vars": [
+				"error",
+				{
+					args: "after-used",
+					argsIgnorePattern: "^_",
+					caughtErrorsIgnorePattern: "^_"
+				}
+			],
+
+			// Too many violations:
+			camelcase: "off",
+			"no-nested-ternary": "off"
+		}
+	},
+	{
+		files: [ "ui/i18n/**/*.js" ],
+		rules: {
+
+			// We want to keep all the strings in separate single lines
+			"max-len": "off"
+		}
+	},
+
+	// Dist files
+	// For dist files, we don't include any jQuery rules on purpose.
+	// We just want to make sure the files are correct ES5.
+	{
+		files: [ "dist/jquery-ui.js", "dist/jquery-ui.min.js" ],
+		languageOptions: {
+			ecmaVersion: 5,
+			sourceType: "script"
+		},
+		linterOptions: {
+			reportUnusedDisableDirectives: "off"
+		}
+	},
+
+	// Build
+	{
+		files: [ "build/**/*.js" ],
+		languageOptions: {
+			ecmaVersion: "latest",
+			sourceType: "commonjs",
+			globals: {
+				...globals.node
+			}
+		},
+		rules: {
+			"no-implicit-globals": "error",
+			strict: [ "error", "global" ]
+		}
+	},
+
+	// Demos
+	{
+		files: [ "demos/**/*.js" ],
+		languageOptions: {
+			globals: {
+				require: true
+			}
+		}
+	},
+
+	// Tests
+	{
+		files: [ "tests/**/*.js" ],
+		languageOptions: {
+			ecmaVersion: 5,
+			sourceType: "script",
+			globals: {
+				...globals.browser,
+				...globals.jquery,
+				define: false,
+				Globalize: false,
+				QUnit: false,
+				require: true,
+				requirejs: true
+			}
+		},
+		"rules": {
+
+			// Too many violations:
+			"max-len": "off",
+			"no-unused-vars": "off",
+			strict: "off" // ideally, `[ "error", "function" ]`
+		}
+	}
+];

Gruntfile.js

@@ -58,13 +58,14 @@
 		"@swc/core": "1.11.5",
 		"commitplease": "3.2.0",
 		"eslint-config-jquery": "3.0.2",
+		"globals": "16.0.0",
 		"grunt": "1.6.1",
 		"grunt-bowercopy": "1.2.5",
 		"grunt-compare-size": "0.4.2",
 		"grunt-contrib-concat": "2.1.0",
 		"grunt-contrib-csslint": "2.0.0",
 		"grunt-contrib-requirejs": "1.0.0",
-		"grunt-eslint": "24.0.1",
+		"grunt-eslint": "25.0.0",
 		"grunt-git-authors": "3.2.0",
 		"grunt-html": "17.1.0",
 		"jquery-test-runner": "0.2.5",

demos/.eslintrc.json

@@ -9,9 +9,7 @@
 
 //>>label: Effects Core
 //>>group: Effects
-/* eslint-disable max-len */
 //>>description: Extends the internal jQuery effects. Includes morphing and easing. Required by all other effects.
-/* eslint-enable max-len */
 //>>docs: https://api.jqueryui.com/category/effects-core/
 //>>demos: https://jqueryui.com/effect/
 
@@ -320,7 +318,7 @@ if ( $.uiBackCompat === true ) {
 			try {
 				// eslint-disable-next-line no-unused-expressions
 				active.id;
-			} catch ( e ) {
+			} catch ( _e ) {
 				active = document.body;
 			}
 

eslint.config.mjs

@@ -9,9 +9,7 @@
 
 //>>label: Explode Effect
 //>>group: Effects
-/* eslint-disable max-len */
 //>>description: Explodes an element in all directions into n pieces. Implodes an element to its original wholeness.
-/* eslint-enable max-len */
 //>>docs: https://api.jqueryui.com/explode-effect/
 //>>demos: https://jqueryui.com/effect/