Vuetable: No rowdata are available in data-item on checkbox-toggled method

I am new to vue table 2.

My issue is no rowdata are available in the data-item on checkbox-toggled method.

here is my code

<vuetable
ref="vuetable"
:api-mode="false"
:fields="fields"
class="panel-body desktop-head-only"
:data="groupData"
@vuetable:checkbox-toggled="checkboxToggledCustom"
@vuetable:checkbox-toggled-all="toggleAllCheckboxes"
>

I don't know anything I missed or not?

This is what am getting on the checkboxToggledCustom method. please check this link