title: Combine object key values into single string with separator
body: <p>I want to achieve this:</p>
  
  <pre><code>var keys = ['name', 'description']
  
  var obj = {
    id: 1,
    name: 'Test',
    description: 'Lorem ipsum dolores',
    moreKeysHere: 'moreValues'
  }
  
  console.log(obsKeysToString(obj, keys, '-'))
  </code></pre>
  
  <p>Result: <code>Test - Lorem ipsum dolores</code></p>
  
  <p>I have some solution with <code>for</code> loop, and some stirring operations and so on but I am sure there's a better way..</p>