ermnvldmr.com/packages/eslint-config/index.js

// @ts-check
import eslint from '@eslint/js';
import prettier from 'eslint-config-prettier/flat';
import importPlugin from 'eslint-plugin-import';
import jsdoc from 'eslint-plugin-jsdoc';
import globals from 'globals';
import tseslint from 'typescript-eslint';

/**
 * Base ESLint configuration
 */
export const baseConfig = tseslint.config(
  {
    ignores: [
      '**/dist',
      '**/node_modules',
      '**/.github',
      '**/.changeset',
      '**/coverage',
      '.config/**/*',
      '*.config.{js,ts,mjs,cjs}',
      '!.storybook', // Allow linting of .storybook directory
    ],
  },

  // JavaScript
  eslint.configs.recommended,

  // TypeScript - Strict Configuration (only for .ts/.tsx files)
  {
    files: ['**/*.{ts,tsx,mts,cts}'],
    extends: [
      ...tseslint.configs.recommendedTypeChecked,
      ...tseslint.configs.stylisticTypeChecked,
    ],
    languageOptions: {
      parserOptions: {
        projectService: true,
        tsconfigRootDir: import.meta.dirname,
      },
    },
    rules: {
      // TypeScript strict rules
      '@typescript-eslint/no-explicit-any': 'error',
      '@typescript-eslint/no-unused-vars': 'error',
      '@typescript-eslint/prefer-nullish-coalescing': 'error',
      '@typescript-eslint/prefer-optional-chain': 'error',
      '@typescript-eslint/no-unnecessary-condition': 'error',
      '@typescript-eslint/no-non-null-assertion': 'error',
      '@typescript-eslint/prefer-as-const': 'error',
      '@typescript-eslint/consistent-type-definitions': ['error', 'interface'],
      '@typescript-eslint/consistent-type-imports': [
        'error',
        { prefer: 'type-imports', disallowTypeAnnotations: false },
      ],
      '@typescript-eslint/explicit-function-return-type': [
        'error',
        { allowExpressions: true, allowTypedFunctionExpressions: true },
      ],
    },
  },

  // Allow triple-slash references in `*.d.ts` files.
  {
    files: ['**/*.d.ts'],
    rules: {
      '@typescript-eslint/triple-slash-reference': 'off',
    },
  },

  // Import/Export Rules
  {
    plugins: { import: importPlugin },
    rules: {
      'import/order': [
        'error',
        {
          groups: [
            'builtin',
            'external',
            'internal',
            ['parent', 'sibling'],
            'index',
            'type',
          ],
          'newlines-between': 'always',
          alphabetize: { order: 'asc', caseInsensitive: true },
        },
      ],
      'import/no-duplicates': 'error',
      'import/no-unused-modules': 'error',
      'import/no-cycle': 'error',
      'import/no-self-import': 'error',
    },
  },

  // JSDoc Requirements - Only for main source code
  {
    files: ['src/**/*.{ts,tsx}', 'packages/**/*.{ts,tsx}', 'services/**/*.{ts,tsx}'],
    plugins: { jsdoc },
    rules: {
      'jsdoc/require-jsdoc': [
        'error',
        {
          contexts: [
            'ExportNamedDeclaration > FunctionDeclaration',
            'ExportDefaultDeclaration > FunctionDeclaration',
            'TSInterfaceDeclaration',
            'TSTypeAliasDeclaration',
          ],
        },
      ],
      'jsdoc/require-description': 'error',
      'jsdoc/require-param': 'error',
      'jsdoc/require-returns': 'error',
      'jsdoc/require-example': 'warn',
      'jsdoc/check-alignment': 'error',
      'jsdoc/check-indentation': 'error',
      'jsdoc/check-syntax': 'error',
      'jsdoc/check-tag-names': 'error',
      'jsdoc/check-types': 'error',
      'jsdoc/valid-types': 'error',
    },
  },

  // Test files
  {
    files: ['**/*.{test,spec}.{js,jsx,ts,tsx}', '.config/jest/**/*.{js,jsx,ts,tsx}'],
    languageOptions: {
      globals: {
        ...globals.jest,
      },
    },
    rules: {
      // Relax rules for test files and jest configuration
      '@typescript-eslint/no-explicit-any': 'off',
      '@typescript-eslint/no-unsafe-assignment': 'off',
      '@typescript-eslint/no-unsafe-call': 'off',
      '@typescript-eslint/no-unsafe-member-access': 'off',
      '@typescript-eslint/no-empty-function': 'off',
      '@typescript-eslint/explicit-function-return-type': 'off',
      'jsdoc/require-jsdoc': 'off',
    },
  },

  // CommonJS files - disable all TypeScript rules
  {
    files: ['**/*.cjs'],
    ...tseslint.configs.disableTypeChecked,
  },

  // Config files and tooling
  {
    files: ['*.config.{js,ts,mjs,cjs}', '.storybook/**/*.{js,ts,cjs,mjs}'],
    rules: {
      '@typescript-eslint/no-explicit-any': 'off',
      '@typescript-eslint/no-unsafe-assignment': 'off',
      '@typescript-eslint/no-unsafe-call': 'off',
      '@typescript-eslint/no-unsafe-member-access': 'off',
      '@typescript-eslint/no-unsafe-argument': 'off',
      '@typescript-eslint/explicit-function-return-type': 'off',
      'jsdoc/require-jsdoc': 'off',
      'no-undef': 'off', // For CommonJS files
    },
  },

  // Prettier
  prettier
);