title: Get the key of a nested object
body: <p>I need a simple method to get the key of a nested object, e.g. <code>description</code>. This is my structure:</p>
  
  <pre><code>let data = [
    {
      name: "Apple",
      id: 1,
      alt: [{ name: "fruit1", description: "tbd1" }]
    },
    {
      name: "Banana",
      id: 2,
      alt: [{ name: "fruit2", description: "tbd2" }]
    },
    {
      name: "Blueberry",
      id: 3,
      alt: [{ name: "fruit3", description: "tbd3" }]
    }
  ];
  </code></pre>