sync.js

const fileSync = file => {
  const stream = require('fs').readFileSync(file, 'utf8').trim()
  console.log(stream)
  return stream
}

const fileAsync = file => {
  const callback = (error, data) => data
  const stream = require('fs').readFile(file, 'utf8',
    callback
  )
  return stream
}

// console.log('fileSync', fileSync('./data'))
// console.log('fileAsync', fileAsync('./data'))