title: group array and get count
body: <p>Say I have array like this:</p>
  
  <pre><code>[
     "foo",
     "bar",
     "foo"
     "bar",
     "bar",
     "bar",
     "zoom"
  ]
  </code></pre>
  
  <p>I want to group it so I can get a count like so:</p>
  
  <pre><code>{
    "foo": 2,
    "bar": 4,
    "zoom": 1
  }
  </code></pre>
  
  <p>is there a utility that can do this?</p>