feat(eslint): add eslint flat config

.eslint/astro.ts

@@ -0,0 +1,28 @@
+import type { Linter } from "eslint";
+// @ts-expect-error - no types available
+import jsxA11y from "eslint-plugin-jsx-a11y";
+import { astroFiles } from "./shared";
+
+export const astroConfig: Linter.Config = {
+  name: "eslint/astro",
+  files: astroFiles,
+  plugins: {
+    "jsx-a11y": jsxA11y,
+  },
+  rules: {
+    // Astro specific adjustments
+    "@typescript-eslint/no-unused-vars": "off", // Astro components can have unused props
+    "import/no-unresolved": "off",
+    "no-undef": "off", // Astro has global variables like Astro
+
+    // A11y rules for Astro
+    "jsx-a11y/alt-text": "error",
+    "jsx-a11y/anchor-has-content": "error",
+    "jsx-a11y/anchor-is-valid": "error",
+    "jsx-a11y/click-events-have-key-events": "error",
+    "jsx-a11y/interactive-supports-focus": "error",
+    "jsx-a11y/no-redundant-roles": "error",
+    "jsx-a11y/img-redundant-alt": "error",
+    "jsx-a11y/no-access-key": "error",
+  },
+};

.eslint/base.ts

@@ -0,0 +1,72 @@
+import type { Linter } from "eslint";
+import { sharedFiles } from "./shared";
+
+export const baseConfig: Linter.Config = {
+  name: "eslint/base",
+  files: sharedFiles,
+  rules: {
+    "constructor-super": "error",
+    "for-direction": "error",
+    "getter-return": "error",
+    "no-async-promise-executor": "error",
+    "no-case-declarations": "error",
+    "no-class-assign": "error",
+    "no-compare-neg-zero": "error",
+    "no-cond-assign": "error",
+    "no-const-assign": "error",
+    "no-constant-binary-expression": "error",
+    "no-constant-condition": "error",
+    "no-control-regex": "error",
+    "no-debugger": "error",
+    "no-delete-var": "error",
+    "no-dupe-args": "error",
+    "no-dupe-class-members": "error",
+    "no-dupe-else-if": "error",
+    "no-dupe-keys": "error",
+    "no-duplicate-case": "error",
+    "no-empty-character-class": "error",
+    "no-empty-pattern": "error",
+    "no-empty-static-block": "error",
+    "no-ex-assign": "error",
+    "no-fallthrough": "error",
+    "no-func-assign": "error",
+    "no-global-assign": "error",
+    "no-import-assign": "error",
+    "no-invalid-regexp": "error",
+    "no-loss-of-precision": "error",
+    "no-misleading-character-class": "error",
+    "no-new-native-nonconstructor": "error",
+    "no-nonoctal-decimal-escape": "error",
+    "no-obj-calls": "error",
+    "no-octal": "error",
+    "no-redeclare": "error",
+    "no-regex-spaces": "error",
+    "no-self-assign": "error",
+    "no-setter-return": "error",
+    "no-this-before-super": "error",
+    "no-undef": "error",
+    "no-unexpected-multiline": "error",
+    "no-unreachable": "error",
+    "no-unsafe-finally": "error",
+    "no-unsafe-negation": "error",
+    "no-unsafe-optional-chaining": "error",
+    "no-unused-labels": "error",
+    "no-unused-private-class-members": "error",
+    "no-useless-backreference": "error",
+    "no-useless-catch": "error",
+    "no-var": "error",
+    "no-with": "error",
+    "require-yield": "error",
+    "use-isnan": "error",
+    "valid-typeof": "error",
+
+    // Additional base rules
+    "no-console": ["warn", { allow: ["warn", "error"] }],
+    "prefer-const": "error",
+    "object-shorthand": "error",
+    "prefer-template": "error",
+    curly: ["error", "all"],
+    eqeqeq: ["error", "always"],
+    "no-implicit-coercion": "error",
+  },
+};

.eslint/config-files.ts

@@ -0,0 +1,19 @@
+import type { Linter } from "eslint";
+import { configFiles } from "./shared";
+
+export const configFilesConfig: Linter.Config = {
+  name: "eslint/config-files",
+  files: configFiles,
+  rules: {
+    "no-console": "off",
+    "@typescript-eslint/no-var-requires": "off",
+    "import/no-default-export": "off",
+    "@typescript-eslint/no-unsafe-assignment": "off",
+    "@typescript-eslint/no-unsafe-member-access": "off",
+    "@typescript-eslint/no-unsafe-call": "off",
+    "@typescript-eslint/no-unsafe-return": "off",
+    "@typescript-eslint/no-unsafe-argument": "off",
+    "prefer-const": "off",
+    "@typescript-eslint/no-explicit-any": "off",
+  },
+};

.eslint/import.ts

@@ -0,0 +1,63 @@
+import type { Linter } from "eslint";
+// @ts-expect-error - no types available
+import importPlugin from "eslint-plugin-import";
+import { sharedFiles } from "./shared";
+
+export const importConfigArray: Linter.Config[] = [
+  {
+    name: "eslint/import",
+    files: sharedFiles,
+    plugins: {
+      import: importPlugin,
+    },
+    rules: {
+      ...importPlugin.configs.recommended.rules,
+      ...importPlugin.configs.typescript.rules,
+
+      "import/order": [
+        "error",
+        {
+          groups: [
+            "builtin",
+            "external",
+            "internal",
+            ["parent", "sibling"],
+            "index",
+            "object",
+            "type",
+          ],
+          "newlines-between": "always",
+          alphabetize: {
+            order: "asc",
+            caseInsensitive: true,
+          },
+          pathGroups: [
+            {
+              pattern: "@/**",
+              group: "internal",
+              position: "before",
+            },
+          ],
+          pathGroupsExcludedImportTypes: ["builtin"],
+        },
+      ],
+      "import/no-unresolved": "off", // TypeScript handles this
+      "import/no-duplicates": ["error", { "prefer-inline": true }],
+      "import/consistent-type-specifier-style": ["error", "prefer-inline"],
+      "import/first": "error",
+      "import/newline-after-import": "error",
+      "import/no-default-export": "off", // Allow default exports
+    },
+    settings: {
+      "import/resolver": {
+        typescript: {
+          alwaysTryTypes: true,
+        },
+        node: true,
+      },
+      "import/parsers": {
+        "@typescript-eslint/parser": [".ts", ".tsx"],
+      },
+    },
+  },
+];

.eslint/javascript.ts

@@ -0,0 +1,35 @@
+import type { Linter } from "eslint";
+import { javascriptFiles } from "./shared";
+
+export const javascriptConfig: Linter.Config = {
+  name: "eslint/javascript",
+  files: javascriptFiles,
+  languageOptions: {
+    ecmaVersion: "latest",
+    sourceType: "module",
+    parserOptions: {
+      ecmaFeatures: {
+        jsx: true,
+      },
+    },
+  },
+  rules: {
+    "no-unused-vars": [
+      "error",
+      {
+        argsIgnorePattern: "^_",
+        varsIgnorePattern: "^_",
+        ignoreRestSiblings: true,
+      },
+    ],
+    "no-console": ["warn", { allow: ["warn", "error"] }],
+    "no-debugger": "error",
+    "prefer-const": "error",
+    "no-var": "error",
+    "object-shorthand": "error",
+    "prefer-template": "error",
+    curly: ["error", "all"],
+    eqeqeq: ["error", "always"],
+    "no-implicit-coercion": "error",
+  },
+};

.eslint/jsx-a11y.ts

@@ -0,0 +1,31 @@
+import type { Linter } from "eslint";
+// @ts-expect-error - no types available
+import jsxA11y from "eslint-plugin-jsx-a11y";
+import { astroFiles, javascriptFiles, typescriptFiles } from "./shared";
+
+export const jsxA11yConfig: Linter.Config = {
+  name: "eslint/jsx-a11y",
+  files: [
+    ...astroFiles,
+    ...typescriptFiles.filter((f) => f.includes("tsx")),
+    ...javascriptFiles.filter((f) => f.includes("jsx")),
+  ],
+  plugins: {
+    "jsx-a11y": jsxA11y,
+  },
+  rules: {
+    ...jsxA11y.configs.recommended.rules,
+
+    // Additional a11y rules
+    "jsx-a11y/alt-text": "error",
+    "jsx-a11y/anchor-has-content": "error",
+    "jsx-a11y/anchor-is-valid": "error",
+    "jsx-a11y/click-events-have-key-events": "error",
+    "jsx-a11y/interactive-supports-focus": "error",
+    "jsx-a11y/no-redundant-roles": "error",
+    "jsx-a11y/img-redundant-alt": "error",
+    "jsx-a11y/no-access-key": "error",
+    "jsx-a11y/label-has-associated-control": "error",
+    "jsx-a11y/no-autofocus": "warn",
+  },
+};

.eslint/react.ts

@@ -0,0 +1,59 @@
+import type { Linter } from "eslint";
+import react from "eslint-plugin-react";
+import { javascriptFiles, typescriptFiles } from "./shared";
+
+export const reactConfig: Linter.Config = {
+  name: "eslint/react",
+  files: [
+    ...typescriptFiles.filter((f) => f.includes("tsx")),
+    ...javascriptFiles.filter((f) => f.includes("jsx")),
+  ],
+  plugins: {
+    react,
+  },
+  rules: {
+    ...react.configs.recommended.rules,
+
+    "react/react-in-jsx-scope": "off", // Not needed in modern React/Preact
+    "react/prop-types": "off", // Using TypeScript
+    "react/jsx-uses-react": "off",
+    "react/jsx-uses-vars": "error",
+    "react/no-unescaped-entities": "off",
+    "react/jsx-key": "error",
+    "react/jsx-no-useless-fragment": "error",
+    "react/self-closing-comp": "error",
+    "react/jsx-boolean-value": ["error", "never"],
+    "react/jsx-curly-brace-presence": [
+      "error",
+      { props: "never", children: "never" },
+    ],
+    "react/function-component-definition": [
+      "error",
+      {
+        namedComponents: "arrow-function",
+        unnamedComponents: "arrow-function",
+      },
+    ],
+  },
+  settings: {
+    react: {
+      version: "detect",
+    },
+  },
+};
+
+import reactHooks from "eslint-plugin-react-hooks";
+
+export const reactHooksConfig: Linter.Config = {
+  name: "eslint/react-hooks",
+  files: [
+    ...typescriptFiles.filter((f) => f.includes("tsx")),
+    ...javascriptFiles.filter((f) => f.includes("jsx")),
+  ],
+  plugins: {
+    "react-hooks": reactHooks,
+  },
+  rules: {
+    ...reactHooks.configs.recommended.rules,
+  },
+};

.eslint/shared.ts

@@ -0,0 +1,41 @@
+export const sharedFiles = [
+  "**/*.js",
+  "**/*.cjs",
+  "**/*.mjs",
+  "**/*.jsx",
+  "**/*.ts",
+  "**/*.cts",
+  "**/*.mts",
+  "**/*.tsx",
+  "**/*.d.ts",
+];
+
+export const sharedTestFiles = [
+  "**/*.test.{ts,tsx,js,jsx}",
+  "**/*.spec.{ts,tsx,js,jsx}",
+  "**/tests/**/*.{ts,tsx,js,jsx}",
+  "**/__tests__/**/*.{ts,tsx,js,jsx}",
+];
+
+export const astroFiles = ["**/*.astro"];
+
+export const typescriptFiles = [
+  "**/*.ts",
+  "**/*.tsx",
+  "**/*.mts",
+  "**/*.cts",
+  "**/*.d.ts",
+];
+
+export const javascriptFiles = ["**/*.js", "**/*.jsx", "**/*.mjs", "**/*.cjs"];
+
+export const configFiles = [
+  "*.config.{ts,js,mjs}",
+  "**/*.config.{ts,js,mjs}",
+  "**/vite.config.*",
+  "**/vitest.config.*",
+  "**/playwright.config.*",
+  "**/astro.config.*",
+  "**/tailwind.config.*",
+  "**/eslint.config.*",
+];

.eslint/test.ts

@@ -0,0 +1,19 @@
+import type { Linter } from "eslint";
+import { sharedTestFiles } from "./shared";
+
+export const testConfig: Linter.Config = {
+  name: "eslint/test",
+  files: sharedTestFiles,
+  rules: {
+    "no-console": "off",
+    "@typescript-eslint/no-explicit-any": "off",
+    "@typescript-eslint/no-non-null-assertion": "off",
+    "@typescript-eslint/no-unsafe-assignment": "off",
+    "@typescript-eslint/no-unsafe-member-access": "off",
+    "@typescript-eslint/no-unsafe-call": "off",
+    "@typescript-eslint/no-unsafe-return": "off",
+    "@typescript-eslint/no-unsafe-argument": "off",
+    "@typescript-eslint/unbound-method": "off",
+    "import/no-extraneous-dependencies": "off",
+  },
+};

.eslint/typescript.ts

@@ -0,0 +1,44 @@
+import type { Linter } from "eslint";
+import { typescriptFiles } from "./shared";
+
+export function createTypescriptConfig(tsConfigPath: string): Linter.Config {
+  return {
+    name: "eslint/typescript",
+    files: typescriptFiles,
+    languageOptions: {
+      parserOptions: {
+        ecmaVersion: "latest",
+        sourceType: "module",
+        ecmaFeatures: {
+          jsx: true,
+        },
+        project: tsConfigPath,
+        tsconfigRootDir: process.cwd(),
+      },
+    },
+    rules: {
+      // Basic TypeScript rules that work without type information
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        {
+          argsIgnorePattern: "^_",
+          varsIgnorePattern: "^_",
+          ignoreRestSiblings: true,
+        },
+      ],
+      "@typescript-eslint/explicit-function-return-type": "off",
+      "@typescript-eslint/explicit-module-boundary-types": "off",
+      "@typescript-eslint/no-explicit-any": "warn",
+      "@typescript-eslint/no-non-null-assertion": "warn",
+      "@typescript-eslint/consistent-type-imports": [
+        "error",
+        { prefer: "type-imports", fixStyle: "inline-type-imports" },
+      ],
+      "@typescript-eslint/consistent-type-definitions": ["error", "type"],
+
+      // Override base rules for TypeScript
+      "no-unused-vars": "off", // Handled by TypeScript
+      "no-undef": "off", // TypeScript handles this
+    },
+  };
+}

.prettierignore

@@ -0,0 +1,47 @@
+# Build outputs
+dist/
+build/
+.astro/
+
+# Dependencies
+node_modules/
+
+# Generated files
+coverage/
+.nyc_output/
+
+# Test outputs
+playwright-report/
+test-results/
+
+# Package files
+package-lock.json
+yarn.lock
+pnpm-lock.yaml
+
+# Config files that should maintain their format
+wrangler.toml
+
+# Binary files
+*.png
+*.jpg
+*.jpeg
+*.gif
+*.svg
+*.ico
+*.woff
+*.woff2
+*.ttf
+*.eot
+
+# IDE and OS
+.vscode/
+.idea/
+
+# Logs
+*.log
+
+# Static assets
+public/fonts/
+public/favicon.ico
+public/favicon.svg

.vscode/settings.json

@@ -0,0 +1,44 @@
+{
+  "editor.formatOnSave": true,
+  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "explicit",
+    "source.organizeImports": "explicit"
+  },
+  "eslint.validate": [
+    "javascript",
+    "javascriptreact",
+    "typescript",
+    "typescriptreact",
+    "astro"
+  ],
+  "eslint.format.enable": false,
+  "prettier.requireConfig": true,
+  "[astro]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[typescript]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[typescriptreact]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[javascript]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[javascriptreact]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[json]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[jsonc]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "[markdown]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode"
+  },
+  "files.associations": {
+    "*.astro": "astro"
+  }
+}

eslint.config.ts

@@ -0,0 +1,93 @@
+import { includeIgnoreFile } from "@eslint/compat";
+import type { TSESLint } from "@typescript-eslint/utils";
+import prettierConfig from "eslint-config-prettier";
+import astro from "eslint-plugin-astro";
+import { dirname, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+import tseslint from "typescript-eslint";
+
+// Import modular configurations
+import { astroConfig } from "./.eslint/astro";
+import { baseConfig } from "./.eslint/base";
+import { configFilesConfig } from "./.eslint/config-files";
+import { importConfigArray } from "./.eslint/import";
+import { javascriptConfig } from "./.eslint/javascript";
+import { jsxA11yConfig } from "./.eslint/jsx-a11y";
+import { reactConfig, reactHooksConfig } from "./.eslint/react";
+import { testConfig } from "./.eslint/test";
+import { createTypescriptConfig } from "./.eslint/typescript";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const tsConfigPath = resolve(__dirname, "./tsconfig.json");
+
+const ignoresConfig = {
+  name: "eslint/ignores",
+  ignores: [
+    // Build outputs
+    "**/dist/**",
+    "**/build/**",
+    "**/.astro/**",
+    "**/node_modules/**",
+
+    // Test outputs
+    "**/coverage/**",
+    "**/playwright-report/**",
+    "**/test-results/**",
+
+    // Config files that don't need linting
+    "**/*.config.js",
+    "**/*.config.mjs",
+    "**/wrangler.toml",
+
+    // Other common ignores
+    "**/.next/**",
+    "**/.nuxt/**",
+    "**/.output/**",
+    "**/.vercel/**",
+    "**/.netlify/**",
+    "**/public/**",
+    "**/*.min.js",
+    "**/*.d.ts",
+    "**/CHANGELOG.md",
+    "**/README.md",
+  ],
+} satisfies TSESLint.FlatConfig.Config;
+
+const config: TSESLint.FlatConfig.ConfigArray = tseslint.config(
+  // Include .gitignore patterns
+  includeIgnoreFile(resolve(__dirname, ".gitignore")),
+
+  // Core configurations
+  ignoresConfig,
+  baseConfig,
+  // TypeScript ecosystem
+  ...tseslint.configs.strict,
+  ...tseslint.configs.stylistic,
+  createTypescriptConfig(tsConfigPath),
+
+  // Import management
+  ...importConfigArray,
+
+  // Framework specific
+  reactConfig,
+  reactHooksConfig,
+  jsxA11yConfig,
+
+  // Astro specific
+  ...astro.configs.recommended,
+  astroConfig,
+
+  // Language specific
+  javascriptConfig,
+
+  // Special cases
+  testConfig,
+  configFilesConfig,
+
+  // Prettier integration (must be last)
+  prettierConfig,
+);
+
+export default config;

package.json

@@ -9,8 +9,12 @@
     "preview": "astro preview --port 3000",
     "wrangler": "wrangler",
     "astro": "astro",
-    "lint": "biome lint ./src",
+    "lint": "eslint . --ext .js,.jsx,.ts,.tsx,.astro",
-    "format": "biome format ./src",
+    "lint:fix": "eslint . --ext .js,.jsx,.ts,.tsx,.astro --fix",
+    "format": "prettier --write .",
+    "format:check": "prettier --check .",
+    "biome:lint": "biome lint ./src",
+    "biome:format": "biome format ./src",
     "prepare": "husky",
     "test": "npx vitest run",
     "test:coverage": "npx vitest --coverage",
@@ -33,6 +37,7 @@
     "clsx": "^2.1.1",
     "date-fns": "^4.1.0",
     "free-astro-components": "^1.2.0",
+    "jiti": "^2.4.2",
     "lucide-astro": "^0.460.0",
     "lucide-react": "^0.475.0",
     "motion": "^11.13.5",
@@ -45,20 +50,44 @@
   },
   "devDependencies": {
     "@biomejs/biome": "^1.9.4",
+    "@eslint/compat": "^1.2.9",
+    "@eslint/eslintrc": "^3.3.1",
+    "@eslint/js": "^9.27.0",
     "@playwright/test": "^1.52.0",
     "@testing-library/jest-dom": "^6.6.3",
     "@testing-library/user-event": "^14.6.1",
     "@types/jsdom": "^21.1.7",
     "@types/node": "^22.15.18",
+    "@typescript-eslint/eslint-plugin": "^8.33.0",
+    "@typescript-eslint/parser": "^8.33.0",
+    "@typescript-eslint/utils": "^8.33.0",
     "@vitest/coverage-istanbul": "^3.1.3",
+    "eslint": "^9.27.0",
+    "eslint-config-prettier": "^10.1.5",
+    "eslint-import-resolver-typescript": "^4.4.1",
+    "eslint-plugin-astro": "^1.3.1",
+    "eslint-plugin-import": "^2.31.0",
+    "eslint-plugin-jsx-a11y": "^6.10.2",
+    "eslint-plugin-react": "^7.37.5",
+    "eslint-plugin-react-hooks": "^5.2.0",
     "husky": "^9.1.7",
     "jsdom": "^26.1.0",
     "lint-staged": "^15.2.7",
+    "prettier": "^3.5.3",
+    "prettier-plugin-astro": "^0.14.1",
+    "prettier-plugin-tailwindcss": "^0.6.11",
+    "typescript-eslint": "^8.33.0",
     "vite-tsconfig-paths": "^5.1.4",
     "vitest": "^3.1.3",
-    "wrangler": "^3.114.8"
+    "wrangler": "^4.17.0"
   },
   "lint-staged": {
-    "src/**/*.{ts,tsx,astro,js,jsx}": ["biome check --write ."]
+    "src/**/*.{ts,tsx,astro,js,jsx}": [
+      "eslint --fix",
+      "prettier --write"
+    ],
+    "src/**/*.{json,md,css}": [
+      "prettier --write"
+    ]
   }
 }

prettier.config.js

@@ -0,0 +1,57 @@
+/**
+ * @type {import('prettier').Config}
+ */
+export default {
+  // Basic formatting
+  printWidth: 100,
+  tabWidth: 2,
+  useTabs: false,
+  semi: false,
+  singleQuote: true,
+  quoteProps: "as-needed",
+  trailingComma: "es5",
+  bracketSpacing: true,
+  bracketSameLine: false,
+  arrowParens: "avoid",
+
+  // Language-specific formatting
+  overrides: [
+    {
+      files: "*.astro",
+      options: {
+        parser: "astro",
+      },
+    },
+    {
+      files: ["*.json", "*.jsonc"],
+      options: {
+        trailingComma: "none",
+      },
+    },
+    {
+      files: ["*.md", "*.mdx"],
+      options: {
+        printWidth: 80,
+        proseWrap: "always",
+      },
+    },
+    {
+      files: ["*.yml", "*.yaml"],
+      options: {
+        singleQuote: false,
+      },
+    },
+  ],
+
+  // Plugins
+  plugins: [
+    "prettier-plugin-astro",
+    "prettier-plugin-tailwindcss", // Must be last
+  ],
+
+  // Plugin-specific options
+  tailwindFunctions: ["clsx", "cn", "twMerge"],
+
+  // Astro-specific options
+  astroAllowShorthand: false,
+};