add eslint, bug fixes

eslint.config.js

@@ -0,0 +1,49 @@
+import eslintPluginAstro from 'eslint-plugin-astro'
+import typescriptParser from '@typescript-eslint/parser'
+import typescriptPlugin from '@typescript-eslint/eslint-plugin'
+import reactPlugin from 'eslint-plugin-react'
+
+export default [
+  ...eslintPluginAstro.configs.recommended,
+  {
+    ignores: [
+      'node_modules/**',
+      'dist/**',
+      '.astro/**',
+      'coverage/**',
+      '*.config.{js,ts,mjs}',
+      '.prettierrc',
+      'package*.json',
+      'tsconfig.json',
+    ],
+    files: ['**/*.{ts,tsx,js,jsx,mjs,cjs}'],
+    plugins: {
+      '@typescript-eslint': typescriptPlugin,
+      react: reactPlugin,
+    },
+    languageOptions: {
+      parser: typescriptParser,
+      parserOptions: {
+        ecmaVersion: 'latest',
+        sourceType: 'module',
+        ecmaFeatures: {
+          jsx: true,
+        },
+        project: './tsconfig.json',
+      },
+    },
+    rules: {
+      ...typescriptPlugin.configs.recommended.rules,
+      'react/jsx-uses-react': 'error',
+      'react/jsx-uses-vars': 'error',
+      'react/react-in-jsx-scope': 'off',
+      'react/prop-types': 'off',
+      '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
+      '@typescript-eslint/no-explicit-any': 'warn',
+      '@typescript-eslint/explicit-function-return-type': 'off',
+      '@typescript-eslint/explicit-module-boundary-types': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'warn',
+      '@typescript-eslint/consistent-type-imports': ['error', { prefer: 'type-imports' }],
+    },
+  },
+]