lint: upgrade eslint to version 9

eslint.config.js

@@ -0,0 +1,206 @@
+import path from 'node:path';
+import {fileURLToPath} from 'node:url';
+import {builtinModules} from "node:module";
+
+import {FlatCompat} from "@eslint/eslintrc";
+import tseslint from 'typescript-eslint';
+
+// plugins
+import prettierEslint from 'eslint-plugin-prettier';
+import noOnlyTestsEslint from 'eslint-plugin-no-only-tests';
+import regexpEslint from 'eslint-plugin-regexp'
+const typescriptEslint = tseslint.plugin;
+
+// parsers
+const typescriptParser = tseslint.parser;
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// ref: https://eslint.org/docs/latest/use/configure/migration-guide#using-eslintrc-configs-in-flat-config
+// mimic CommonJS variables -- not needed if using CommonJS
+const compat = new FlatCompat({
+	baseDirectory: __dirname
+});
+
+export default [
+	// If ignores is used without any other keys in the configuration object, then the patterns act as global ignores.
+	// ref: https://eslint.org/docs/latest/use/configure/configuration-files#globally-ignoring-files-with-ignores
+	{
+		ignores: [
+			"**/.*",
+			"**/*.d.ts",
+			"packages/**/*.min.js",
+			"packages/**/dist/",
+			"packages/**/fixtures/",
+			"packages/astro/vendor/vite/",
+			"benchmark/**/dist/",
+			"examples/",
+			"scripts/",
+			".github/",
+			".changeset/",
+		]
+	},
+
+	...tseslint.configs.recommendedTypeChecked,
+	...tseslint.configs.stylisticTypeChecked,
+	// mimic ESLintRC-style extends
+	...compat.extends('prettier'),
+	...compat.extends('plugin:regexp/recommended'),
+	{
+		languageOptions: {
+			parser: typescriptParser,
+			parserOptions: {
+				project: ['./packages/*/tsconfig.json', './tsconfig.eslint.json'],
+				tsconfigRootDir: __dirname,
+			},
+		},
+		plugins: {
+			"@typescript-eslint": typescriptEslint,
+			"prettier": prettierEslint,
+			"no-only-tests": noOnlyTestsEslint,
+			"regexp": regexpEslint,
+		},
+		rules: {
+			// These off/configured-differently-by-default rules fit well for us
+			'@typescript-eslint/switch-exhaustiveness-check': 'error',
+			'@typescript-eslint/no-unused-vars': [
+				'warn',
+				{
+					argsIgnorePattern: '^_',
+					varsIgnorePattern: '^_',
+					caughtErrorsIgnorePattern: '^_',
+					ignoreRestSiblings: true,
+				},
+			],
+			'no-only-tests/no-only-tests': 'error',
+			'@typescript-eslint/no-shadow': 'error',
+			'no-console': 'warn',
+
+			// Todo: do we want these?
+			'@typescript-eslint/array-type': 'off',
+			'@typescript-eslint/ban-ts-comment': 'off',
+			'@typescript-eslint/class-literal-property-style': 'off',
+			'@typescript-eslint/consistent-indexed-object-style': 'off',
+			'@typescript-eslint/consistent-type-definitions': 'off',
+			'@typescript-eslint/dot-notation': 'off',
+			'@typescript-eslint/no-base-to-string': 'off',
+			'@typescript-eslint/no-empty-function': 'off',
+			'@typescript-eslint/no-floating-promises': 'off',
+			'@typescript-eslint/no-misused-promises': 'off',
+			'@typescript-eslint/no-redundant-type-constituents': 'off',
+			'@typescript-eslint/no-this-alias': 'off',
+			'@typescript-eslint/no-unsafe-argument': 'off',
+			'@typescript-eslint/no-unsafe-assignment': 'off',
+			'@typescript-eslint/no-unsafe-call': 'off',
+			'@typescript-eslint/no-unsafe-member-access': 'off',
+			'@typescript-eslint/no-unsafe-return': 'off',
+			'@typescript-eslint/no-unnecessary-type-assertion': 'off',
+			'@typescript-eslint/prefer-nullish-coalescing': 'off',
+			'@typescript-eslint/prefer-optional-chain': 'off',
+			'@typescript-eslint/prefer-string-starts-ends-with': 'off',
+			'@typescript-eslint/require-await': 'off',
+			'@typescript-eslint/restrict-plus-operands': 'off',
+			'@typescript-eslint/restrict-template-expressions': 'off',
+			'@typescript-eslint/sort-type-constituents': 'off',
+			'@typescript-eslint/unbound-method': 'off',
+			'@typescript-eslint/no-explicit-any': 'off',
+
+			// Enforce separate type imports for type-only imports to avoid bundling unneeded code
+			'@typescript-eslint/consistent-type-imports': [
+				'error',
+				{
+					prefer: 'type-imports',
+					fixStyle: 'separate-type-imports',
+					disallowTypeAnnotations: false,
+				},
+			],
+
+			// These rules enabled by the preset configs don't work well for us
+			'@typescript-eslint/await-thenable': 'off',
+			'prefer-const': 'off',
+
+			// In some cases, using explicit letter-casing is more performant than the `i` flag
+			'regexp/use-ignore-case': 'off',
+		},
+	},
+
+	{
+		// Ensure Node builtins aren't included in Astro's server runtime
+		files: ['packages/astro/src/runtime/**/*.ts'],
+		rules: {
+			'no-restricted-imports': [
+				'error',
+				{
+					paths: [...builtinModules],
+					patterns: ['node:*'],
+				},
+			],
+		},
+	},
+	{
+		files: ['packages/astro/src/runtime/client/**/*.ts'],
+		languageOptions: {
+			globals: {
+				browser: true,
+			}
+		},
+	},
+	{
+		files: ['packages/**/test/*.js', 'packages/**/*.js'],
+		languageOptions: {
+			globals: {
+				mocha: true,
+				globalThis: false, // false means read-only
+			}
+		},
+		rules: {
+			'no-console': 'off',
+		},
+	},
+	{
+		files: ['packages/integrations/**/*.ts'],
+		rules: {
+			'no-console': ['error', {allow: ['warn', 'error', 'info', 'debug']}],
+		},
+	},
+	{
+		files: ['benchmark/**/*.js'],
+		rules: {
+			'@typescript-eslint/no-unused-vars': 'off',
+			'no-console': 'off',
+		},
+	},
+	{
+		files: ['packages/db/**/cli/**/*.ts'],
+		rules: {
+			'no-console': 'off',
+		},
+	},
+	{
+		files: ['packages/astro/src/core/errors/errors-data.ts'],
+		rules: {
+			// This file is used for docs generation, as such the code need to be in a certain format, we can somewhat ensure this with these rules
+			'object-shorthand': ['error', 'methods', {avoidExplicitReturnArrows: true}],
+			'arrow-body-style': ['error', 'never'],
+		},
+	},
+
+	{
+		files: ['packages/db/src/runtime/**/*.ts'],
+		rules: {
+			'no-restricted-imports': 'off',
+			'@typescript-eslint/no-restricted-imports': [
+				'error',
+				{
+					patterns: [
+						{
+							group: ['../core/*'],
+							allowTypeImports: true,
+						},
+					],
+				},
+			],
+		},
+	},
+]