title: How to sorting by date string with mat-sort-header?
body: <p>I have a case table constructed with <code>angular.material</code> and I need to add sorting by date. But my date is a <code>string</code> type, and so sorting incorrectly. How to overriding default <code>mat-sort-header</code> behavior. And it's possible?</p>
  
  <pre><code>&lt;div class="example-container mat-elevation-z8"&gt;
      &lt;mat-table #table [dataSource]="dataSource" matSort&gt;
  
          &lt;!-- Reg Date Column --&gt;
          &lt;ng-container matColumnDef="regDate"&gt;
              &lt;mat-header-cell *matHeaderCellDef mat-sort-header&gt; Reg Date &lt;/mat-header-cell&gt;
              &lt;mat-cell *matCellDef="let element"&gt; {{element.regDate}} &lt;/mat-cell&gt;
          &lt;/ng-container&gt;
          &lt;mat-header-row *matHeaderRowDef="displayedColumns"&gt;&lt;/mat-header-row&gt;
          &lt;mat-row *matRowDef="let row; columns: displayedColumns;"&gt;&lt;/mat-row&gt;
      &lt;/mat-table&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>And on TS side:</p>
  
  <pre><code>sort: MatSort;
  @ViewChild(MatSort)
  set appBacon(sort : MatSort) {
      this.sort = sort;
      this.dataSource.sort = this.sort;
  }
  dataSource = new MatTableDataSource([]);
  </code></pre>