title: Access object properties React-Native
body: <p>I have a response from the server that looks like this</p>
  
  <pre><code>[  
     {  
        "metric":{  
           "id":"b66178b8-dc18-11e8-9f8b-f2801f1b9fd1",
           "name":"Detector de fum bucatarie",
           "metricValueType":"DOUBLE",
           "metricType":"DEVICE_VALUE",
           "groupUUID":null,
           "projectUUID":null,
           "companyUUID":"ccab28ed-3dcf-411f-8748-ec7740ae559c",
           "unit":null,
           "formula":null
        },
        "data":{  
           "1550150771819":"10.310835857351371"
        }
     }
  ]
  </code></pre>
  
  <p>Data property contains a hashMap with Timestamp and a Value. 
  When I try to get any value I recive this error: </p>
  
  <p><code>myErrorTypeError: undefined is not an object (evaluating 'metricValues.metric.id')</code></p>
  
  <p>How can I access a property ? I tried both methods :</p>
  
  <p><code>metricValues.metric.id</code> </p>
  
  <p>and</p>
  
  <p><code>metricValues["metric"]["id"]</code></p>
  
  <p>How can I get the hashMap values?
  I already tried this :</p>
  
  <pre><code>const timestamp = Object.keys(metricValues.data)[0];
  const values = Object.values(metricValues.data)[0];
  </code></pre>