title: How to fetch key of key object in JavaScript
body: <p>I want to fetch the key of key from this object keys can be anything from time to time so i can not use specific key
  here is the data </p>
  
  <pre><code>{
          "test": {
              "4": [
                  {
                  some data
                  }
              ]
          },
          "case": {
              "2": [
                  {
                      some data
                  },
                  {
                      some data
                  }
              ]
          }
      }
  </code></pre>
  
  <p>I have tried this to fetch it is fine but I want fetch only 2nd key, in example i just want to get key not complete object and the thing is i can not specifically mention the data like <code>test</code> or <code>case</code> it can be anything its dynamic.</p>
  
  <pre><code>let vv = _.get(obj,'test')
  console.log(vv)
   {
              "4": [
                  {
                  some data
                  }
              ]
          }
  </code></pre>