hack.js

nativeElement.addEventListener('focus', focusListener, true);
nativeElement.addEventListener('blur', blurListener, true);

document.addEventListener('keydown', documentKeydownListener, true);
document.addEventListener('mousedown', documentMousedownListener, true);
document.addEventListener('touchstart', documentTouchstartListener, true);
window.addEventListener('focus', windowFocusListener);

let documentKeydownListener = () => {
  this._lastTouchTarget = null;
  this._setOriginForCurrentEventQueue('keyboard');
};

let documentMousedownListener = () => {
  if (!this._lastTouchTarget) {
    this._setOriginForCurrentEventQueue('mouse');
  }
};

let documentTouchstartListener = (event: TouchEvent) => {
  if (this._touchTimeoutId != null) {
    clearTimeout(this._touchTimeoutId);
  }
  this._lastTouchTarget = event.target;
  this._touchTimeoutId = setTimeout(() => this._lastTouchTarget = null, TOUCH_BUFFER_MS);
};

let windowFocusListener = () => {
  this._windowFocused = true;
  this._windowFocusTimeoutId = setTimeout(() => this._windowFocused = false);
};