.eslintrc.js

module.exports = {
  env: {
    browser: true,
    es2021: true,
  },
  extends: [
    'eslint:recommended',
    'plugin:react/recommended',
    'plugin:import/typescript',
    'plugin:@typescript-eslint/recommended',

    // override all prettier rules, see https://github.com/prettier/eslint-config-prettier
    'prettier',
  ],
  parser: '@typescript-eslint/parser',
  parserOptions: {
    ecmaFeatures: {
      jsx: true,
    },
    ecmaVersion: 12,
    sourceType: 'module',
    project: './tsconfig.json',
  },
  plugins: ['import', 'react', '@typescript-eslint'],
  rules: {
    // A few more opinions in addition to extensions

    // As per React 17 changes! https://reactjs.org/blog/2020/09/22/introducing-the-new-jsx-transform.html
    'react/react-in-jsx-scope': 'off',
    'react/jsx-uses-react': 'off',

    'linebreak-style': ['error', 'unix'],

    '@typescript-eslint/no-require-imports': ['error'],

    '@typescript-eslint/no-non-null-assertion': 'off',

    '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],

    // 2 space indentation
    '@typescript-eslint/indent': ['error', 2],

    // Style
    quotes: ['error', 'single', { avoidEscape: true }],

    // Require all imported dependencies are actually declared in package.json
    'import/no-extraneous-dependencies': [
      'error',
      {
        optionalDependencies: false, // Disallow importing optional dependencies (those shouldn't be in use in the project)
        peerDependencies: false, // Disallow importing peer dependencies (that aren't also direct dependencies)
      },
    ],

    // Require all imported libraries actually resolve (!!required for import/no-extraneous-dependencies to work!!)
    'import/no-unresolved': ['error'],

    // Require an ordering on all imports
    'import/order': [
      'warn',
      {
        groups: ['builtin', 'external'],
        alphabetize: { order: 'asc', caseInsensitive: true },
      },
    ],

    // Cannot import from the same module twice
    'no-duplicate-imports': ['error'],

    // Cannot shadow names
    // note you must disable the base rule as it can report incorrect errors
    'no-shadow': 'off',
    '@typescript-eslint/no-shadow': ['error'],

    // Required spacing in property declarations (copied from TSLint, defaults are good)
    'key-spacing': ['error'],

    // Require semicolons
    semi: ['error', 'always'],

    // Don't unnecessarily quote properties
    'quote-props': ['error', 'consistent-as-needed'],

    // No multiple empty lines
    'no-multiple-empty-lines': ['error'],

    // Max line lengths
    'max-len': [
      'error',
      {
        code: 120,
        ignoreUrls: true, // Most common reason to disable it
        ignoreStrings: true, // These are not fantastic but necessary for error messages
        ignoreTemplateLiterals: true,
        ignoreRegExpLiterals: true,
      },
    ],

    // One of the easiest mistakes to make
    '@typescript-eslint/no-floating-promises': ['error'],

    // Don't leave log statements littering the premises!
    'no-console': ['error', { allow: ['info', 'warn', 'error'] }],

    // Useless diff results
    'no-trailing-spaces': ['error'],

    // Must use foo.bar instead of foo['bar'] if possible
    'dot-notation': ['error'],

    // Are you sure | is not a typo for || ?
    'no-bitwise': ['error'],

    // Member ordering
    '@typescript-eslint/member-ordering': [
      'error',
      {
        default: [
          'public-static-field',
          'public-static-method',
          'protected-static-field',
          'protected-static-method',
          'private-static-field',
          'private-static-method',

          'field',

          // Constructors
          'constructor', // = ['public-constructor', 'protected-constructor', 'private-constructor']

          // Methods
          'method',
        ],
      },
    ],
  },
};