handleSelectWord method Null safety

Implementation

@protected
SelectionResult handleSelectWord(SelectWordSelectionEvent event) {
  for (int index = 0; index < selectables.length; index += 1) {
    final Rect localRect = Rect.fromLTWH(0, 0, selectables[index].size.width, selectables[index].size.height);
    final Matrix4 transform = selectables[index].getTransformTo(null);
    final Rect globalRect = MatrixUtils.transformRect(transform, localRect);
    if (globalRect.contains(event.globalPosition)) {
      final SelectionGeometry existingGeometry = selectables[index].value;
      dispatchSelectionEventToChild(selectables[index], event);
      if (selectables[index].value != existingGeometry) {
        // Geometry has changed as a result of select word, need to clear the
        // selection of other selectables to keep selection in sync.
        selectables
          .where((Selectable target) => target != selectables[index])
          .forEach((Selectable target) => dispatchSelectionEventToChild(target, const ClearSelectionEvent()));
        currentSelectionStartIndex = currentSelectionEndIndex = index;
      }
      return SelectionResult.end;
    }
  }
  return SelectionResult.none;
}