JSFiddle - React, Tailwind, and code Playground

JavaScript

function onError(e) {
    console.log(e);
}

function onInitFileSystem(fs) {
   writeFile(fs);
}

function writeFile(fs) {
  fs.root.getFile('log.txt', {create: true}, function(fileEntry) {
    fileEntry.createWriter(function(fileWriter) {
      fileWriter.onwriteend = function(e) {
        console.log('Write completed.');
      };
      var bb = new WebKitBlobBuilder();
      bb.append('Lorem Ipsum');
      fileWriter.write(bb.getBlob('text/plain'));
      readFile(fs);
    }, onError);
  }, onError);
}

function readFile(fs) {
      fs.root.getFile('log.txt', {}, function(fileEntry) {
    
    // Get a File object representing the file,
    // then use FileReader to read its contents.
    fileEntry.file(function(file) {
       var reader = new FileReader();
    
       reader.onloadend = function(e) {
         var txtArea = document.createElement('textarea');
         txtArea.value = this.result;
         document.body.appendChild(txtArea);
       };
    
       reader.readAsText(file);
    }, onError);
    
    }, onError);
}

window.webkitRequestFileSystem(window.TEMPORARY, 1024*1024, onInitFileSystem, onError);