title: Check if all values of array are equal
body: <p>I need to find arrays where all values are equal. What's the fastest way to do this? Should I loop through it and just compare values?</p>
  
  <pre><code>['a', 'a', 'a', 'a'] // true
  ['a', 'a', 'b', 'a'] // false
  </code></pre>