남의 코드를 읽어보자!

const {
  children,
  disabled = false,
  noFocusGuards = false,
  persistentFocus = false,
  crossFrame = true,
  autoFocus = true,
  allowTextSelection,
  group,
  className,
  whiteList,
  hasPositiveIndices,
  shards = emptyArray,
  as: Container = "div",
  lockProps: containerProps = {},
  sideCar: SideCar,

  returnFocus: shouldReturnFocus = false,
  focusOptions,

  onActivation: onActivationCallback,
  onDeactivation: onDeactivationCallback,
} = props;

const observed = React.useRef();
const isActive = React.useRef(false);
const originalFocusedElement = React.useRef(null);

const onActivation = React.useCallback(() => {
  originalFocusedElement.current =
    originalFocusedElement.current || (document && document.activeElement);
  if (observed.current && onActivationCallback) {
    onActivationCallback(observed.current);
  }
  isActive.current = true;
}, [onActivationCallback]);