ESLint e Prettier

ESlint

Caso haja um arquivo .eslintrc previamente existente, deve-se remover este arquivo e instalar o ESLint rodando $yarn add eslint -D.

Executar o comando o $ yarn eslint --init

? How would you like to use ESLint? # To check syntax, find problems, and enforce code style
? What type of modules does your project use? # JavaScript modules (import/export)
? Which framework does your project use? # React
? Does your project use TypeScript? # No
? Where does your code run? # NENHUM
? How would you like to define a style for your project? # Use a popular style guide
? Which style guide do you want to follow? # Airbnb: https://github.com/airbnb/javascript
? What format do you want your config file to be in? # JavaScript

Apagar o package.lock.json e rodar o $ yarn

Prettier

Instalar o prettier e demais dependências $ yarn add prettier eslint-config-prettier eslint-plugin-prettier babel-eslint -D

Arquivo .eslintrc.js

module.exports = {
  env: {
    es6: true,
  },
  extends: [
    'airbnb',
    'prettier',
    'prettier/react'
  ],
  globals: {
    Atomics: 'readonly',
    SharedArrayBuffer: 'readonly',
    __DEV__: 'readonly'
  },
  parser: 'babel-eslint',
  parserOptions: {
    ecmaFeatures: {
      jsx: true,
    },
    ecmaVersion: 2018,
    sourceType: 'module',
  },
  plugins: [
    'react',
    'prettier'
  ],
  rules: {
    'prettier/prettier': 'error',
    'react/jsx-filename-extension': [
      'warn',
      { extensions: ['.jsx', '.js'] }
    ],
    'import/prefer-default-export': 'off',
  },
};

Arquivo .prettierrc

{
  "singleQuote": true,
  "trailingComma": "es5"
}