const fs = require('fs')
const EventEmmiter = require('events')

class HandleFiles extends EventEmmiter {
  readFile(path, opts) {
    fs.readFile(path, opts, (err, data) => {
      if (err) throw new Error(err)

      const content = Buffer.from(data, 'base64').toString()
      this.emit('readFileDone',content)
    })
  }
  writeFile (path, content) {
    fs.writeFile(path, content, err => {
      if (err) throw new Error(err)
      this.emit('writeFileDone')
    })
  }
}

const handleFiles = new HandleFiles();


handleFiles.on('readFileDone', (content) => handleFiles.writeFile('./content.txt',content));
handleFiles.on('writeFileDone', ()=>console.log('The file has been written correctly.'))
handleFiles.readFile('base64.txt', 'utf-8')