title: javascript count objects in array of objects without null values
body: <p>Let's say we have array of objects:</p>
  
  <pre><code>const data = [
    {
      firstName: "Bruce",
      lastName: "Wayne",
      address: "Arkham 6",
      id: "1",
    },
    {
      firstName: "Peter",
      lastName: "Parker",
       address: "LA 54",
      id: "2"
    },
    {
      firstName: "Tony",
      lastName: "Stark",
      address: null,
      id: "3"
    }
  ];
  </code></pre>
  
  <p>and want to get length of the array but exclude counting of the objects which has null values (in example above, this is the last object with address property <code>null</code>) so that result of the counting of the example above would be 2.</p>
  
  <pre><code>objectsWithoutNull = data.reduce(function (r, a) {
      return r + +( a!== null);
  }, 0);
  </code></pre>
  
  <p>I'm trying with reduce method, but got 0.
  Where is the problem in iteration?</p>