title: PrimeNG filter using array object
body: <p>I wanted to know if it was possible to use an array of objects for filtering something into a table ?</p>
  
  <p>I'm using Angular 6 and PrimeNG 7</p>
  
  <p>My p-table looks like this: </p>
  
  <pre><code>&lt;p-table #table class="ui-table ui-table-responsive" [value]="arrays"  [columns]="cols" &gt;
      ...
      &lt;div class="col-xl-4"&gt;        
      &lt;i class="fa fa-search" style="margin:4px 4px 0 0"&gt;&lt;/i&gt;
      &lt;input type="text" pInputText size="50" placeholder="Rechercher" (input)="table.filter($event.target.value, cols['sort'], 'contains')" style="width:auto"&gt;
      &lt;/div&gt;
      ...
  &lt;p-table&gt;
  </code></pre>
  
  <p>I want to use <strong>filter()</strong> and not <strong>globalFilter()</strong> because i need to specify the field that i want to filter.</p>
  
  <p>The content of cols is this:</p>
  
  <pre><code>this.cols = [
    { field: 'number', sort: 'number', header: 'The number' },
    { field: 'type', sort: 'type', header: 'The type' },
    { field: 'place', field2: 'placeName', sort: 'place.placeName', header: 'The place'},
    { field: 'city', field2: 'cityName',  sort: 'city.cityName', header: 'The city' },
    ...
    ...
  ];
  </code></pre>
  
  <p>For the moment my filter won't work..</p>