title: moment's isSameOrBefore and isSameOrAfter return "is not a function" when called from a moment and passed a moment
body: <p>Why do <strong>momentjs</strong> <code>isSameOrBefore</code> and <code>isSameOrAfter</code> functions does not work for data which <code>isBefore</code> and <code>isAfter</code> work for?</p>
  
  <p>Here are some very simple isolated examples where <code>isSameOrBefore</code> and <code>isSameOrAfter</code> does not work:</p>
  
  <pre><code>moment("2018-10-12 10:44:01").isSameOrBefore(moment("2018-10-12 10:44:00"))
  TypeError: moment(...).isSameOrBefore is not a function [Learn More]
  
  moment("2018-10-12 10:44:01").isSameOrAfter(moment("2018-10-12 10:44:02"))
  TypeError: moment(...).isSameOrAfter is not a function [Learn More]
  </code></pre>
  
  <p>But yet with the same kind of data, <code>isBefore</code> and <code>isAfter</code> work fine:</p>
  
  <pre><code>moment("2018-10-12 10:44:01").isBefore(moment("2018-10-12 10:44:00"))
  false
  moment("2018-10-12 10:44:01").isAfter(moment("2018-10-12 10:44:02"))
  false
  moment("2018-10-12 10:44:00").isBefore(moment("2018-10-12 10:44:01"))
  true
  moment("2018-10-12 10:44:02").isAfter(moment("2018-10-12 10:44:01"))
  true
  </code></pre>