title: setting values if they don't already exist
body: <p>What's the best way for setting values if they don't already exist in PHP?</p>
  
  <p>Is it safe to use</p>
  
  <pre><code>$color = $option['color'] ?: 'blue';
  </code></pre>
  
  <p>Instead of</p>
  
  <pre><code>$color = isset($option['color']) ? $option['color'] : 'blue';
  </code></pre>
  
  <p>Or there's a much better way?</p>