is there $index iterator for wjFlexChart binding (wijmo 5 flex chart)?

Question

as I understand data-bind="wjFlexChart: { itemsSource: data, bindingX: 'week' } iterates through all items in array data (like foreach knockout binding).

My questions are:
1) how can I access current element Id ($index doesn't work)?
2) are $data, $parent the same as $data, $parent for knockout foreach binding?