Migrate to ESLint 9 (#6685)

* Migrate to ESLint 9
* https://eslint.org/docs/latest/use/migrate-to-9.0.0
* https://eslint.style/guide/migration
* https://github.com/neostandard/neostandard/ (https://github.com/standard/standard/issues/1948)

fix broken Dependabot PRs such as https://github.com/FreshRSS/FreshRSS/pull/6680

* comma-dangle rule is already included

* Use more standard filename

* More flexible syntax globals

* resolveIgnoresFromGitignore

* Dependabog update

* Relax object-shorthand

* GitHub action node-version

* GitHub action node-version again

* object-shorthand: off

* node >=18 due to dependencies

.eslintignore

@@ -1,6 +0,0 @@
-.git/
-*.min.js
-extensions/
-node_modules/
-p/scripts/vendor/
-vendor/

.eslintrc.json

@@ -1,29 +0,0 @@
-{
-	"env": {
-		"browser": true
-	},
-	"extends": [
-		"eslint:recommended",
-		"standard"
-	],
-	"rules": {
-		"camelcase": "off",
-		"comma-dangle": ["warn", {
-			"arrays": "always-multiline",
-			"objects": "always-multiline"
-		}],
-		"eqeqeq": "off",
-		"indent": ["warn", "tab", { "SwitchCase": 1 }],
-		"linebreak-style": ["error", "unix"],
-		"max-len": ["warn", 165],
-		"no-tabs": "off",
-		"semi": ["warn", "always"],
-		"space-before-function-paren": ["warn", {
-			"anonymous": "always",
-			"named": "never",
-			"asyncArrow": "always"
-		}],
-		"yoda": "off"
-	},
-	"root": true
-}

.github/dependabot.yml

@@ -13,10 +13,12 @@ updates:
     groups:
       eslint:
         patterns:
-          - "eslint*"
+          - "*eslint*"
+          - "globals"
+          - "neostandard"
       stylelint:
         patterns:
-          - "stylelint*"
+          - "*stylelint*"
   - package-ecosystem: "composer"
     directory: "/"
     schedule:

.github/workflows/tests.yml

@@ -58,8 +58,8 @@ jobs:
       uses: actions/setup-node@v4
       with:
         # https://nodejs.org/en/about/previous-releases
-        node-version: '20'
-        cache: 'npm'
+        node-version: lts/*
+        cache: npm
 
     - run: npm ci
 

eslint.config.js

@@ -0,0 +1,55 @@
+import globals from "globals";
+import js from "@eslint/js";
+import neostandard, { resolveIgnoresFromGitignore } from 'neostandard';
+import stylistic from '@stylistic/eslint-plugin';
+
+export default [
+	{
+		files: ["**/*.js"],
+		languageOptions: {
+			globals: {
+				...globals.browser,
+			},
+			sourceType: "script",
+		},
+	},
+	{
+		ignores: [
+			...resolveIgnoresFromGitignore(),
+			"**/*.min.js",
+			"extensions/",
+			"p/scripts/vendor/",
+		],
+	},
+	js.configs.recommended,
+	// stylistic.configs['recommended-flat'],
+	...neostandard(),
+	{
+		plugins: {
+			"@stylistic": stylistic,
+		},
+		rules: {
+			"camelcase": "off",
+			"eqeqeq": "off",
+			"no-empty": ["error", { "allowEmptyCatch": true }],
+			"no-unused-vars": ["error", {
+				"args": "none",
+				"caughtErrors": "none",
+			}],
+			"object-shorthand": "off",
+			"yoda": "off",
+			"@stylistic/indent": ["warn", "tab", { "SwitchCase": 1 }],
+			"@stylistic/linebreak-style": ["error", "unix"],
+			"@stylistic/max-len": ["warn", 165],
+			"@stylistic/no-tabs": "off",
+			"@stylistic/quotes": ["off", "single", { "avoidEscape": true }],
+			"@stylistic/quote-props": ["warn", "consistent"],
+			"@stylistic/semi": ["warn", "always"],
+			"@stylistic/space-before-function-paren": ["warn", {
+				"anonymous": "always",
+				"asyncArrow": "always",
+				"named": "never",
+			}],
+		},
+	},
+];

package.json

@@ -1,5 +1,6 @@
 {
   "name": "freshrss",
+  "type": "module",
   "description": "A free, self-hostable aggregator",
   "homepage": "https://freshrss.org/",
   "readmeFilename": "README.md",
@@ -19,11 +20,11 @@
   },
   "license": "AGPL-3.0",
   "engines": {
-    "node": ">=16"
+    "node": ">=18"
   },
   "scripts": {
-    "eslint": "eslint --ext .js .",
-    "eslint_fix": "eslint --fix --ext .js .",
+    "eslint": "eslint .",
+    "eslint_fix": "eslint --fix .",
     "markdownlint": "markdownlint '**/*.md'",
     "markdownlint_fix": "markdownlint --fix '**/*.md'",
     "rtlcss": "rtlcss -d p/themes/ && find p/themes/ -type f -name '*.rtl.rtl.css' -delete",
@@ -33,15 +34,14 @@
     "fix": "npm run rtlcss && npm run stylelint_fix && npm run eslint_fix && npm run markdownlint_fix"
   },
   "devDependencies": {
-    "eslint": "^8.57.0",
-    "eslint-config-standard": "^17.1.0",
-    "eslint-plugin-import": "^2.29.1",
-    "eslint-plugin-n": "^16.6.2",
-    "eslint-plugin-promise": "^6.1.1",
+    "eslint": "^9.8.0",
+    "@eslint/js": "^9.8.0",
+    "globals": "^15.9.0",
     "markdownlint-cli": "^0.41.0",
+    "neostandard": "^0.11.2",
     "rtlcss": "^4.2.0",
     "sass": "^1.77.8",
-    "stylelint": "^16.6.1",
+    "stylelint": "^16.8.1",
     "stylelint-config-recommended-scss": "^14.1.0",
     "stylelint-order": "^6.0.4",
     "@stylistic/stylelint-plugin": "^3.0.0"