Function useGridCell

packages/react-aria/src/grid/useGridCell.ts:75–319

(
  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 = 'child', shouldSelectOnPressUp, onAction} = props;

  let {direction} = useLocale();
  let {
    keyboardDelegate,
    actions: {onCellAction}
  } = gridMap.get(state)!;

  // 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()) {
          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);
      }
    }
  };

  let {itemProps, isPressed} = useSelectableItem({
    selectionManager: state.selectionManager,
    key: node.key,
    ref,
    isVirtualized,
    focus,
    shouldSelectOnPressUp,
    onAction: onCellAction ? () => onCellAction(node.key) : onAction,
    isDisabled: state.collection.size === 0
  });