title: Javascript loop trough array of object and return one object containing only keys that have their values changed
body: <p>I have an array of objects I need to loop through and check if the key of the object has different value. If so return this key.</p>
  
  <pre><code>const arrayOfObjects = [
    { item: { first_name: "Joe", last_name: "Dow", age: 15 } },
    { item: { first_name: "Joe", last_name: "d", age: 15 } },
    { item: { first_name: "Joe", last_name: "Dow", age: 20 } }
  ];
  </code></pre>
  
  <p>expected result should be </p>
  
  <pre><code>const result = {
    last_name: true,
    age: true
  }
  </code></pre>
  
  <p>PS: each object has always the same number of keys</p>