title: Fast way to concatenate strings in nodeJS/JavaScript
body: <p>I understand that doing something like</p>
  
  <pre><code>var a = "hello";
  a += " world";
  </code></pre>
  
  <p>It is relatively very slow, as the browser does that in <code>O(n)</code> . Is there a faster way of doing so without installing new libraries? </p>