title: how can I concatenate two arrays in javascript?
body: <p>I saw this <a href="https://stackoverflow.com/questions/1374126/how-to-extend-an-existing-javascript-array-with-another-array">response</a> for extending one array with another
  so I tried:</p>
  
  <pre><code>console.log(['a', 'b'].push.apply(['c', 'd']));
  </code></pre>
  
  <p>but it prints:</p>
  
  <pre><code>2
  </code></pre>
  
  <p>shouldn't it print:</p>
  
  <pre><code>['a', 'b', 'c', 'd']
  </code></pre>
  
  <p>if not what was i doing wrong?</p>