How to connect two inputs in the same form - html

Question

I'm doing a form that have a multiple checklist, the user can select whatever they want and they neet to put a date, I already configured the checklist but, How can I connect the input date to the input checkbox because they need to be related to.
Soo my final result should be like:
results [{ 'Tramit1', 'date1' }, { 'Tramit2', 'date2' }];
Here's my current code of the part I'm talking about (because the form is bigger):
<table class="table table-bordered">
<thead>
<tr>
<th> # </th>
<th>Tràmit</th>
<th>Validesa de l'autorització</th>
</tr>
</thead>
<tbody>
<tr *ngFor="let permiso of permisos">
<td id="first">
<div class="form-check form-check-aj">
<label class="form-check-label">
<input (change)="onChange(permiso.nom, $event.target.checked)" type="checkbox" class="form-check-input">
<i class="input-helper"></i></label>
</div>
</td>
<td id="first">{{permiso.nom}}</td>
<td>
<div id="datepicker-popup" class="input-group date datepicker">
<input type="date" id="datePicker{{permiso.id}}" name="bday" />
<span class="input-group-addon input-group-append border-left">
<span class="mdi mdi-calendar input-group-text"></span>
</span>
</div>
</td>
</tr>
</tbody>
</table>