title: Merge/flatten an array of arrays
body: <p>I have a JavaScript array like:</p>
  
  <pre><code>[["$6"], ["$12"], ["$25"], ["$25"], ["$18"], ["$22"], ["$10"]]
  </code></pre>
  
  <p>How would I go about merging the separate inner arrays into one like:</p>
  
  <pre><code>["$6", "$12", "$25", ...]
  </code></pre>