eslint.config.mjs

// @ts-check

import eslint from '@eslint/js';
import tseslint from 'typescript-eslint';
import eslintPrettierConfig from 'eslint-plugin-prettier/recommended';
import simpleImportSort from 'eslint-plugin-simple-import-sort';

/**
 * @returns {import('typescript-eslint').ConfigWithExtends}
 */
function buildBaseConfig() {
  return {
    extends: [
      eslint.configs.recommended,
      ...tseslint.configs.strictTypeChecked,
    ],
    languageOptions: {
      parser: tseslint.parser,
      parserOptions: {
        project: './tsconfig.json',
      },
    },
    plugins: {
      '@typescript-eslint': tseslint.plugin,
      'simple-import-sort': simpleImportSort,
    },
    rules: {
      '@typescript-eslint/consistent-type-definitions': ['error', 'interface'],
      '@typescript-eslint/explicit-member-accessibility': [
        'error',
        {
          overrides: {
            constructors: 'no-public',
          },
        },
      ],
      '@typescript-eslint/member-ordering': ['warn'],
      '@typescript-eslint/naming-convention': [
        'error',
        {
          selector: ['classProperty'],
          format: ['strictCamelCase', 'UPPER_CASE', 'snake_case'],
          leadingUnderscore: 'allow',
        },
        {
          selector: 'typeParameter',
          format: ['StrictPascalCase'],
          prefix: ['T'],
        },
        {
          selector: ['typeLike'],
          format: ['StrictPascalCase'],
        },
        {
          selector: ['function', 'classMethod'],
          format: ['strictCamelCase'],
          leadingUnderscore: 'allow',
        },
        {
          selector: ['parameter'],
          format: ['strictCamelCase'],
          leadingUnderscore: 'allow',
        },
        {
          selector: ['variableLike'],
          format: ['strictCamelCase', 'UPPER_CASE', 'snake_case'],
        },
      ],
      '@typescript-eslint/no-deprecated': 'error',
      '@typescript-eslint/no-duplicate-type-constituents': 'off',
      '@typescript-eslint/no-dynamic-delete': 'error',
      '@typescript-eslint/no-extraneous-class': 'off',
      '@typescript-eslint/no-inferrable-types': 'off',
      '@typescript-eslint/no-empty-interface': 'warn',
      '@typescript-eslint/no-explicit-any': 'error',
      '@typescript-eslint/no-floating-promises': ['error'],
      '@typescript-eslint/no-unsafe-enum-comparison': 'off',
      'no-magic-numbers': 'off',
      '@typescript-eslint/no-magic-numbers': [
        'warn',
        {
          ignore: [0, 1],
          ignoreArrayIndexes: true,
          ignoreEnums: true,
          ignoreReadonlyClassProperties: true,
        },
      ],
      '@typescript-eslint/no-require-imports': 'error',
      '@typescript-eslint/no-unnecessary-type-arguments': 'off',
      '@typescript-eslint/no-unused-expressions': ['error'],
      '@typescript-eslint/no-useless-constructor': 'error',
      '@typescript-eslint/prefer-for-of': 'error',
      '@typescript-eslint/prefer-nullish-coalescing': ['off'],
      '@typescript-eslint/prefer-optional-chain': 'off',
      '@typescript-eslint/prefer-readonly': ['warn'],
      '@typescript-eslint/promise-function-async': ['error'],
      '@typescript-eslint/require-await': 'off',
      '@typescript-eslint/restrict-plus-operands': [
        'error',
        {
          skipCompoundAssignments: false,
        },
      ],
      '@typescript-eslint/typedef': [
        'error',
        {
          arrayDestructuring: true,
          arrowParameter: true,
          memberVariableDeclaration: true,
          objectDestructuring: true,
          parameter: true,
          propertyDeclaration: true,
          variableDeclaration: true,
        },
      ],
      '@typescript-eslint/unified-signatures': 'error',
      '@typescript-eslint/strict-boolean-expressions': 'error',
      '@typescript-eslint/switch-exhaustiveness-check': [
        'error',
        {
          considerDefaultExhaustiveForUnions: true,
        },
      ],
      '@typescript-eslint/no-unused-vars': [
        'warn',
        {
          args: 'all',
          argsIgnorePattern: '^_',
          caughtErrors: 'all',
          caughtErrorsIgnorePattern: '^_',
          destructuredArrayIgnorePattern: '^_',
          varsIgnorePattern: '^_',
          ignoreRestSiblings: true,
        },
      ],
      'simple-import-sort/imports': [
        'error',
        {
          groups: [['^\\u0000'], ['^node:'], ['^@?\\w'], ['^'], ['^\\.']],
        },
      ],
      'sort-keys': [
        'error',
        'asc',
        {
          caseSensitive: false,
          natural: true,
        },
      ],
    },
  };
}

const baseRules = buildBaseConfig();

const config = tseslint.config(
  {
    ...baseRules,
    files: ['**/*.ts'],
    ignores: ['**/*.test.ts'],
  },
  {
    ...baseRules,
    files: ['**/*.test.ts'],
    rules: {
      ...(baseRules.rules ?? {}),
      '@typescript-eslint/no-confusing-void-expression': 'off',
      '@typescript-eslint/unbound-method': 'off',
      '@typescript-eslint/no-magic-numbers': 'off',
    },
  },
  /** @type {import('typescript-eslint').ConfigWithExtends} */ (
    eslintPrettierConfig
  ),
);

export default [...config];