text: const lowerCaseFirst = ([first, ...rest]) => first.toLowerCase() + rest.join('')
  
  const upperCaseFirst = ([first, ...rest]) => first.toUpperCase() + rest.join('')
  
  console.log(lowerCaseFirst('Foobar')) // foobar
  
  console.log(upperCaseFirst('foobar')) // Foobar
  