title: Is it possible to get an array of unique values in firebase?
body: <p>Consider the following data stored in Firebase:</p>
  
  <pre class="lang-js prettyprint-override"><code>{
    "beers": {
      "-jwhkclclmecl": {
        "name": "Two Hearted Ale",
        "type": "IPA",
        "brewery": "Bells"
      },
      "-ckqjheh292od": {
        "name": "Dirty Blonde Ale",
        "type": "Pale Wheat",
        "brewery": "Atwater"
      },
      "-hcwiu3cp902d": {
        "name": "Diabolical",
        "type": "IPA",
        "brewery": "North Peak"
      }
    }
  }
  </code></pre>
  
  <p>Is it possible to build a query for Firebase to return an array of the unique values of one of the child nodes. For example to return <code>["IPA", "Pale Wheat"]</code></p>