bad.ts

let pp = this.proposalForm;
    let $datefields = $('.date input').datepicker(
      {
        format: "dd/mm/yyyy"
      }
    );

    $datefields.on('changeDate', function (e) {
      let fcn = $(this).attr('formControlName');
      let index = e;
      index = index.currentTarget || null;
      index = index.attributes || null;
      index = index['data-cpd'] || null;
      if (index) { index = index.nodeValue || null; }
      if (index) {
        let carray = pp.controls.competitor_analysis as FormArray;
        let grp = carray.controls[index] as FormGroup;
        grp.controls[fcn].setValue(moment(e.date).format("DD/MM/YYYY"))
        grp.controls[fcn].markAsDirty();
      } else {
        pp.controls[fcn].setValue(moment(e.date).format("DD/MM/YYYY"));
        pp.controls[fcn].markAsDirty();
      }
    });