I am using AngularFire2 within an Angular web app. Due to the query limitations of Firebase, I can't form a query that delivers exactly the data I need (At least not without making major changes to my schema). 

So I want to apply an additional client-side filter criteria within javascript (typescript). How do I do this? Can I somehow add a filter function to the observable? Below is a fragment that illustrates what I'm doing.

In the HTML Template for the component, I have something like this below. The "jobs" variable in the html fragment is a FirebaseListObservable. 

```
<tr *ngFor="let job of jobs | async"> 
  .. fill in the table rows

```

The component code looks like this:

```
   // in the member declaration of the class
   jobs : FirebaseListObservable<Job[]>;

   ...
   // Notice in ngOnInit(), I'm filtering the jobs list using the the
   // Firebase criteria. But I want to filter on an additional field. 
   // Firebase allows only single field criteria, so I'm looking for 
   // a way to apply an additional client-side filter to jobs to eliminate
   // some additional records. 

   ngOnInit(){
      this.jobs = this.af.database.list("/jobs/", {query: {orderByChild : "companyKey", equalTo:someKey}})
   }

```

Is there a way to apply a filter component on "this.jobs" so that I can apply a local (client-side) filter?