Function useGridCell

packages/react-aria/src/grid/useGridCell.ts:83–393

(
  props: GridCellProps,
  state: GridState<T, C>,
  ref: RefObject<FocusableElement | null>
)

 * @param state - State of the parent grid, as returned by `useGridState`.
 */
export function useGridCell<T, C extends GridCollection<T>>(
  props: GridCellProps,
  state: GridState<T, C>,
  ref: RefObject<FocusableElement | null>
): GridCellAria {
  let {
    node,
    isVirtualized,
    focusMode: focusModeProp,
    allowsArrowNavigation,
    shouldSelectOnPressUp,
    onAction
  } = props;

  let {direction} = useLocale();
  let {
    keyboardDelegate,
    actions: {onCellAction},
    keyboardNavigationBehavior
  } = gridMap.get(state)!;
  let focusMode = focusModeProp ?? (keyboardNavigationBehavior === 'tab' ? 'cell' : 'child');

  // We need to track the key of the item at the time it was last focused so that we force
  // focus to go to the item when the DOM node is reused for a different item in a virtualizer.
  let keyWhenFocused = useRef<Key | null>(null);

  // Handles focusing the cell. If there is a focusable child,
  // it is focused, otherwise the cell itself is focused.
  let focus = () => {
    if (ref.current) {
      let treeWalker = getFocusableTreeWalker(ref.current);
      if (focusMode === 'child') {
        // If focus is already on a focusable child within the cell, early return so we don't shift focus
        if (
          isFocusWithin(ref.current) &&
          ref.current !== getActiveElement(getOwnerDocument(ref.current))
        ) {
          return;
        }

        let focusable =
          state.selectionManager.childFocusStrategy === 'last'
            ? last(treeWalker)
            : (treeWalker.firstChild() as FocusableElement);
        if (focusable) {
          focusSafely(focusable);
          return;
        }
      }

      if (
        (keyWhenFocused.current != null && node.key !== keyWhenFocused.current) ||
        !isFocusWithin(ref.current)
      ) {
        focusSafely(ref.current);
      }
    }
  };