title: What is preferred way to implement uniq or uniqBy filter for Array/List?
body: <p>There seems no straight implementing uniq or uniqBy filter for Array/List</p>
  <p><code>[&quot;val1&quot;, &quot;val2&quot;, &quot;val1&quot;]</code> -&gt; <code>[&quot;val1&quot;, &quot;val2&quot;]</code></p>
  <p><code>[&quot;key1&quot; /\ 1, &quot;key2&quot; /\ 10, &quot;key1&quot; /\ 20]</code> -&gt; <code>[&quot;key1&quot; /\ 1, &quot;key2&quot; /\ 10]</code></p>
  <p>There can be many ways of doing this, but what is the preferred/better way to in terms of performance/simplicity?</p>