function saveFile(text, name = 'file', mime = 'text/plain') {

  const blob = new Blob([

    text

  ], { type: mime });

  const a = document.createElement('a')

  a.download = name + '.txt'

  a.href = window.URL.createObjectURL(blob)

  a.click();

}

// hacky way to create the button and have it call `saveFile`

// when clicked

document.body.appendChild(

  Object.assign(

    document.createElement`button`,

  { innerText: 'click me' })

).onclick = () => saveFile('Hello there')

const fs = require('fs');

function writeNextFile(file, content, files, done) {

  fs.writeFile(file, content + '\n', () => {

    const next = files.shift();

    if (!next && done != null) {

      done();

      return;

    }

    writeNextFile(next.file, next.content, files, done);

  });

}

function writeFiles(files, cb) {

  const curr = files.shift();

  writeNextFile(curr.file, curr.content, files, cb);

}

writeFiles(

  [

    {

      file: 'zevan1.txt',

      content: 'hello world'

    },

    {

      file: 'zevan2.txt',

      content: 'goodbye world'

    },

    {

      file: 'confusing.txt',

      content: 'greetings world'

    }

  ],

  () => {

    console.log('done');

  }

);