selector-example.ts

const focusedVirtualCellSelector = createSelectorMemoizedV8(
  gridRenderContextSelector,
  gridFocusCellSelector,

  currentRowsSelector,
  visibleColumnsSelector,

  (currentRenderContext, focusedCell, currentRows, visibleColumns) => {

    if (!focusedCell) {
      return null;
    }

    const rowIndex = currentRows.findIndex((row) => row.id === focusedCell.id);
    const columnIndex = visibleColumns.findIndex((column) => column.field === focusedCell.field);

    if (rowIndex === -1 || columnIndex === -1) {
      return null;
    }

    const isFocusedCellInContext =
      rowIndex >= currentRenderContext.firstRowIndex &&
      rowIndex <= currentRenderContext.lastRowIndex &&
      columnIndex >= currentRenderContext.firstColumnIndex &&
      columnIndex <= currentRenderContext.lastColumnIndex;

    if (isFocusedCellInContext) {
      return null;
    }

    return {
      ...focusedCell,
      rowIndex,
      columnIndex,
    };
  },
);

// usage
const focusedVirtualCell = useGridSelectorV8(apiRef, focusedVirtualCellSelector)