title: how to filter custom data type (link) in ng-2 smart table
body: <p>I am using filters in the cols of an ng2 smart table in an angular 5 project. The following code is working correctly.</p>
  
  <pre><code>columns: 
    service_start_date: {
      title: "DOS",
      filter: true,
      sort: true
    },
  </code></pre>
  
  <p>However, when the cell is a custom Component of link type, this is not working. I tried a custom filter with filterFunction(). That also did not work.</p>
  
  <pre><code>columns: {
    id: {
      title: "Enc #",
      type: "custom",
      renderComponent: LinkRenderComponent,
      filter: true,
      sort: true,
      filterFunction(cell?: any, search?: string): boolean {          
        if (cell === search || search === '') {
          return true;
        } else {
          return false;
        }          
      }
    },
  </code></pre>
  
  <p>This is my LinkRenderComponent's ts file.</p>
  
  <pre><code>export class LinkRenderComponent implements ViewCell, OnInit {
  
  constructor(
      private router: Router
    ) { }
  renderValue: string;
  renderText: string;
  hrefValue : string;
  
  @Input() value: string | number;
  @Input() rowData: any;
  
  ngOnInit() {
    this.renderValue = this.rowData.encounter_procedure_id;
    this.renderText = this.rowData.encounter_id;
    this.hrefValue = '/home/ar-report/' ;
    }
  }
  </code></pre>
  
  <p>I understand I may have to make it work in this file. Where in this file do I make it work? How do I pass to this file the value in the row header's text filter? This seems configured to take as input the value in the cell and the value set that is the row.</p>