With reactive forms

   

Form is valid: {{form.valid}}
Form values: {{form.value | json}}
start date is touched? {{form.get('date').touched}}

Code:
<form [formGroup]="form">
      <div class="row">
        <div class="col-sm-3">
            <div class="form-group">
                <div class="input-group date" data-target-input="nearest" NgTempusdominusBootstrap>
                    <input
                    class="form-control"
                    formControlName="date"
                    [options]="options"
                    NgTempusdominusBootstrapInput
                    type="text"
                    />
                    <div class="input-group-append" NgTempusdominusBootstrapToggle>
                        <div class="input-group-text"><i class="fa fa-calendar"></i></div>
                    </div>
                </div>
            </div>
        </div>
  </form>