JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/aurora.js/0.4.2/aurora.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/aurora.js-flac/0.2.1/flac.min.js"></script>
<input type="file" id="file-input" />
<button>play</button>

CSS

input {
  display: block;
  margin-bottom: 6px;
}
button {
  display: none
}

JavaScript

var $fileInput = $('#file-input');
var $btn = $('button');
var isPlaying = false;
var player;

function readFile(e) {
  if(window.FileReader) {
    var file  = e.target.files[0];
    var reader = new FileReader();
    if (file && file.type.match('audio/flac')) {
      reader.readAsArrayBuffer(file);
    } else {
      console.log('Please add a flac file.')
    }
    reader.onloadend = function (e) {
      player = AV.Player.fromBuffer(reader.result)
      $btn.show()
      $btn.on('click', function() {
        if(isPlaying) {
          player.pause();
          isPlaying = false;
          this.textContent = 'play'
        } else {
          player.play();
          isPlaying = true;
          this.textContent = 'pause'
        }
      })
    }
  }
}

$fileInput.on('change', readFile)