eslint.config.js

// @ts-check
import js from '@eslint/js';
import prettierConfig from 'eslint-config-prettier';
import globals from 'globals';

/** @type {import('eslint').Linter.FlatConfig[]} */
const config = [
  js.configs.recommended,
  prettierConfig,
  {
    languageOptions: {
      ecmaVersion: 'latest',
      sourceType: 'module',
      globals: {
        ...globals.es2021,
        ...globals.node,
      },
    },
    rules: {
      // overrides
      'no-unused-vars': ['error', { ignoreRestSiblings: true }],

      // important
      'no-shadow': 'error',

      // possible errors
      eqeqeq: 'error',
      'no-constant-binary-expression': 'error',
      'no-duplicate-imports': 'error',
      'no-return-assign': 'error',
      'no-sequences': 'error',

      // preference/style
      'no-else-return': 'error',
      'no-return-await': 'error',
      'no-var': 'error',
      'require-await': 'error',
      'spaced-comment': ['error', 'always'],

      // not needed with typescript checking, copied from https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/eslint-plugin/src/configs/eslint-recommended.ts
      // (this repo currently doesn't use typescript-eslint)
      'constructor-super': 'off', // ts(2335) & ts(2377)
      'getter-return': 'off', // ts(2378)
      'no-const-assign': 'off', // ts(2588)
      'no-dupe-args': 'off', // ts(2300)
      'no-dupe-class-members': 'off', // ts(2393) & ts(2300)
      'no-dupe-keys': 'off', // ts(1117)
      'no-func-assign': 'off', // ts(2539)
      'no-import-assign': 'off', // ts(2539) & ts(2540)
      'no-new-symbol': 'off', // ts(7009)
      'no-obj-calls': 'off', // ts(2349)
      'no-redeclare': 'off', // ts(2451)
      'no-setter-return': 'off', // ts(2408)
      'no-this-before-super': 'off', // ts(2376)
      'no-undef': 'off', // ts(2304)
      'no-unreachable': 'off', // ts(7027)
      'no-unsafe-negation': 'off', // ts(2365) & ts(2360) & ts(2358)
      'valid-typeof': 'off', // ts(2367)
    },
  },
];

export default config;