⬆️ Upgrade to ESLint 9 (#55)

⬆️ Upgrade to ESLint 9

.vscode/settings.json

@@ -4,6 +4,7 @@
 		"editor.minimap.maxColumn": 100,
 		"editor.rulers": [100]
 	},
+	"eslint.useFlatConfig": true,
 	"files.associations": {
 		"*.eslintignore": "ignore",
 		"*.prettierignore": "ignore"

eslint.config.js

@@ -0,0 +1,77 @@
+import eslint from '@eslint/js'
+import prettier from 'eslint-config-prettier'
+import svelte from 'eslint-plugin-svelte'
+import globals from 'globals'
+import svelteParser from 'svelte-eslint-parser'
+import tseslint from 'typescript-eslint'
+
+export default tseslint.config(
+	{
+		files: ['.js', '.mjs', '.mts', '.svelte', '.ts'].flatMap(e => [`**/*${e}`, `*${e}`]),
+		// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+		extends: [
+			// eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
+			eslint.configs.recommended,
+			...tseslint.configs.strictTypeChecked,
+			...tseslint.configs.stylisticTypeChecked,
+			prettier,
+		],
+		languageOptions: {
+			globals: { ...globals.browser, ...globals.node },
+			parser: tseslint.parser,
+			parserOptions: { extraFileExtensions: ['.svelte'], project: './tsconfig.eslint.json' },
+		},
+		rules: {
+			'@typescript-eslint/class-methods-use-this': [
+				'error',
+				{ ignoreClassesThatImplementAnInterface: true, ignoreOverrideMethods: true },
+			],
+			'@typescript-eslint/consistent-type-exports': 'error',
+			'@typescript-eslint/consistent-type-imports': [
+				'error',
+				{ fixStyle: 'separate-type-imports' },
+			],
+			'@typescript-eslint/default-param-last': 'error',
+			'@typescript-eslint/explicit-member-accessibility': ['error', { accessibility: 'no-public' }],
+			'@typescript-eslint/method-signature-style': 'error',
+			'@typescript-eslint/no-import-type-side-effects': 'error',
+			'@typescript-eslint/no-unnecessary-qualifier': 'error',
+			'@typescript-eslint/no-useless-empty-export': 'error',
+			'@typescript-eslint/prefer-nullish-coalescing': ['error', { ignorePrimitives: true }],
+			'@typescript-eslint/prefer-readonly': 'error',
+			'@typescript-eslint/prefer-regexp-exec': 'error',
+			'@typescript-eslint/promise-function-async': ['error', { checkArrowFunctions: false }],
+			'@typescript-eslint/require-array-sort-compare': 'error',
+			'@typescript-eslint/return-await': 'error',
+			'@typescript-eslint/sort-type-constituents': 'error',
+			'@typescript-eslint/switch-exhaustiveness-check': 'error',
+			'func-style': ['error', 'declaration'],
+
+			// SvelteKit uses that for returning errors in routes
+			'@typescript-eslint/no-throw-literal': 'off',
+		},
+	},
+
+	{
+		extends: [...svelte.configs['flat/recommended'], ...svelte.configs['flat/prettier']],
+		files: ['.svelte'].flatMap(e => [`**/*${e}`, `*${e}`]),
+		languageOptions: {
+			globals: globals.browser,
+			parser: svelteParser,
+			parserOptions: { parser: tseslint.parser, project: './tsconfig.eslint.json' },
+		},
+	},
+
+	{
+		ignores: [
+			'.pnpm-store',
+			'.svelte-kit',
+			'build',
+			'dist',
+			'node_modules',
+			'package',
+			'vite.config.js.timestamp-*',
+			'vite.config.ts.timestamp-*',
+		],
+	},
+)

package.json

@@ -28,19 +28,19 @@
 		"docker:kill": "docker ps --format '{{.Image}} {{.ID}}' | grep lmgtfy | awk '{print $2}' | xargs docker kill"
 	},
 	"devDependencies": {
+		"@eslint/js": "^9.2.0",
 		"@natoboram/heroicons.svelte": "^1.0.6",
 		"@playwright/test": "^1.31.2",
 		"@sveltejs/adapter-auto": "^3.2.0",
 		"@sveltejs/adapter-node": "^5.0.1",
 		"@sveltejs/adapter-static": "^3.0.1",
 		"@sveltejs/kit": "^2.5.7",
 		"@sveltejs/vite-plugin-svelte": "^3.1.0",
-		"@typescript-eslint/eslint-plugin": "^7.5.0",
-		"@typescript-eslint/parser": "^7.5.0",
 		"autoprefixer": "^10.4.19",
-		"eslint": "^8.57.0",
+		"eslint": "^9.2.0",
 		"eslint-config-prettier": "^9.1.0",
-		"eslint-plugin-svelte": "^2.35.1",
+		"eslint-plugin-svelte": "^2.38.0",
+		"globals": "^15.1.0",
 		"postcss": "^8.4.38",
 		"prettier": "^3.2.5",
 		"prettier-plugin-svelte": "^3.2.3",
@@ -50,6 +50,7 @@
 		"tailwindcss": "^3.4.3",
 		"tslib": "^2.6.2",
 		"typescript": "^5.4.5",
+		"typescript-eslint": "^7.8.0",
 		"vite": "^5.2.10",
 		"vitest": "^1.6.0"
 	},