.prettierrc.js

module.exports = {
  arrowParens: 'always',
  bracketSameLine: false,
  bracketSpacing: true,
  htmlWhitespaceSensitivity: 'css',
  insertPragma: false,
  jsxSingleQuote: true,
  printWidth: 120,
  proseWrap: 'preserve',
  quoteProps: 'as-needed',
  requirePragma: false,
  semi: false,
  singleQuote: true,
  tabWidth: 2,
  trailingComma: 'none',
  useTabs: false
}

 arrowParens : alwaysの時 Arrow関数の引数が１つでも括弧がつく。avoid の時付かない