Double Keypress Detection

dblkeypress.js

document.addEventListener('dblkeypress', function (event) {
  console.log('event: ', event);
  console.log('----Works----');
}, false);

var dblkeypressConfig = {
  lastKeyCode: null,
  lastFiredTime: null,
  interval: 500, // 500(slow) or 350(medium) or 100(fast) or 50(impossible)
  clear: function () {
    dblkeypressConfig.lastKeyCode = dblkeypressConfig.lastFiredTime = null;
  }
}

var dblkeypressEvent = document.createEvent('Event');
dblkeypressEvent.initEvent('dblkeypress', true, true);
document.addEventListener('keyup', function (event) {
  var keyCode = event.keyCode || event.which;
  var milliSeconds = (new Date).getTime();

  if(dblkeypressConfig.lastFiredTime !== null && (dblkeypressConfig.lastFiredTime + dblkeypressConfig.interval) < milliSeconds) {
    dblkeypressConfig.clear();
  }

  if (dblkeypressConfig.lastKeyCode !== null && dblkeypressConfig.lastKeyCode === keyCode) {
    this.dispatchEvent(dblkeypressEvent);
  }

  dblkeypressConfig.lastKeyCode = keyCode;
  dblkeypressConfig.lastFiredTime = milliSeconds;
}, false);

listeningMultiKeyPresses.js

var keysPressed = {};
document.addEventListener('keydown', (event) => {
  keysPressed[event.key] = true;

  if (keysPressed['Control'] && event.key == 'c') {
    console.log('keysPressed: ', keysPressed);
  }
});

document.addEventListener('keyup', (event) => {
  delete keysPressed[event.key];
});