title: Angular material 10: Making a Date range picker open-ended
body: <p>One of the noteworthy changes in Angular 10 was the oft-requested feature of date range selection:
  <a href="https://material.angular.io/components/datepicker/overview#date-range-selection" rel="nofollow noreferrer">https://material.angular.io/components/datepicker/overview#date-range-selection</a></p>
  <p>It enables you to select a start date and an end date in the same picker.</p>
  <p>I want to use this input in a form I need, in order to filter records from a database. However, per requirements, I should be able to leave either the start date or the end date unspecified. So, I should be able to cover all the following example scenarios:</p>
  <ol>
  <li><strong>15 May 2020 to 30 June 2020</strong>: Select all records with dates in the given range</li>
  <li><strong><em>Unspecified</em> to 30 June 2020</strong>: Select all records with dates up to 30 June.</li>
  <li><strong>15 May 2020 to <em>Unspecified</em></strong>: Select all records from 15 May onwards.</li>
  </ol>
  <p>Accomplishing case 1 is pretty easy. I'm not sure how to go about accomplishing case 2 and 3.</p>
  <p>Can anyone help?</p>