title: Convert 2D Array Into 1D Array
body: <p>I have this 2 dimensional array:</p>
  
  <pre><code>var list = [
      ['zone_1', 'zone_2'],
      ['zone_3']
  ]
  </code></pre>
  
  <p>I want to merge all elements in the sub-arrays into a single array:</p>
  
  <pre><code>var list = [
      'zone_1',
      'zone_2',
      'zone_3'
  ]
  </code></pre>
  
  <p>How can I do that in node.js?
  It is possible to do it without using a loop or map?</p>