How to mark ngbDatepicker Valid in form even when no value is selected

angular, ng-bootstrap, ngb-datepicker

Solution

The issue was with how I was initializing the form values. I was setting the default values to empty strings where I should have been initializing the dates to null. So I was doing this:

  replicantForm = this.fb.group({
      name: ['', Validators.required],
      incepdate: '',
      longevity: ''
  })

When I should have been doing this:

  replicantForm = this.fb.group({
      name: ['', Validators.required],
      incepdate: null,
      longevity: ''
  })

Many thanks to @pkozlowski-opensource for the clarification.

Problem

I'm making use of ng-bootstrap's ngbDatepicker in a Reactive Form in an Angular2 project, and the dates are optional, however ngbDatepicker always marks the form as Invalid unless a date is selected. Is there a way to exclude ngbDatepicker from the form validation, or to configure it so that it returns Valid whether it has a value set or not?

Original source