title: React ag grid conditional cellrenderer
body: <p>I want the props cellRenderer: 'agGroupCellRenderer' work conditionally.
  ex,</p>
  
  <pre><code>{
        headerName: 'testname',
        valueGetter: params =&gt; {
          return .....;
        },
        cellRenderer: 'agGroupCellRenderer',
        cellRendererParams: {
          suppressCount: true,
        },
  }
  </code></pre>
  
  <p>if params.data.type==='group', then cellRenderer: 'agGroupCellRenderer', otherwise, cellRenderer:''(just do not render it as group).</p>
  
  <p>I did something like </p>
  
  <pre><code>cellRenderer: params =&gt; {
          return params.data.group=== 'Y' ? cellRenderer:'agGroupCellRenderer' : '';
        },
  </code></pre>
  
  <p>but it just returns the string 'agGroupCellRenderer'</p>