Tablesort date bug

Tablesort incorrectly chooses the date sort

by thorncp

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/tablesort/5.0.0/tablesort.min.js"></script>
<table id="things">
  <thead>
    <th>Header 1</th>
  </thead>
  <tbody>
    <tr><td>Common</td></tr>
    <tr><td>Common</td></tr>
    <tr><td>Common</td></tr>
    <tr><td>Series A</td></tr>
    <tr><td>Preferred</td></tr>
  </tbody>
</table>

CSS

th[role=columnheader]:not(.no-sort) {
	cursor: pointer;
}

th[role=columnheader]:not(.no-sort):after {
	content: '';
	float: right;
	margin-top: 7px;
	border-width: 0 4px 4px;
	border-style: solid;
	border-color: #404040 transparent;
	visibility: hidden;
	opacity: 0;
	-ms-user-select: none;
	-webkit-user-select: none;
	-moz-user-select: none;
	user-select: none;
}

th[aria-sort=ascending]:not(.no-sort):after {
	border-bottom: none;
	border-width: 4px 4px 0;
}

th[aria-sort]:not(.no-sort):after {
	visibility: visible;
	opacity: 0.4;
}

th[role=columnheader]:not(.no-sort):hover:after {
	visibility: visible;
	opacity: 1;
}

JavaScript

// tablesort.date
!function(){var a=function(a){return a=a.replace(/\-/g,"/"),a=a.replace(/(\d{1,2})[\/\-](\d{1,2})[\/\-](\d{2})/,"$1/$2/$3"),new Date(a).getTime()||-1};Tablesort.extend("date",function(b){return(-1!==b.search(/(Mon|Tue|Wed|Thu|Fri|Sat|Sun)\.?\,?\s*/i)||-1!==b.search(/\d{1,2}[\/\-]\d{1,2}[\/\-]\d{2,4}/)||-1!==b.search(/(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)/i))&&!isNaN(a(b))},function(b,c){return b=b.toLowerCase(),c=c.toLowerCase(),a(c)-a(b)})}();

new Tablesort(document.getElementById("things"));