let _context;
function getContext() {
  if (!_context) {
    _context = new AudioContext();
  }
  return _context;
}

function loadSample(url) {
  return fetch(url)
    .then((response) => response.arrayBuffer())
    .then((buffer) => getContext().decodeAudioData(buffer));
}

function playSoundSample(sample, sampleNote, noteToPlay) {
  const ctx = getContext();
  const source = ctx.createBufferSource();
  source.buffer = sample;
  source.playbackRate.value = 2 ** ((noteToPlay - sampleNote) / 12);
  source.connect(ctx.destination);
  source.start(0);
}