title: How to call service from ag-grid valueFormatter
body: <p>Does anyone know how to call service from ValueFormatter of ag-grid in Angular2+?</p>
  
  <p>Example: </p>
  
  <p>I have injected a service called someService in the constructor and would like to call the service from the ValueFormatter. What should i do to achieve that?</p>
  
  <pre><code>constructor(private service: SomeService) { }
  
  this.columnDefs.push(
          {
              headerName: 'Date',
              width: 150,
              field: 'incidentDate',
              valueFormatter(params) {
                  return this.service.doSomething(params.value);
              }
          });
  </code></pre>
  
  <p>At the moment, it doesn't recognise the service from the valueFormatter.</p>
  
  <p>Thanks in advance</p>