title: can I get node to output commas in number strings without bringing in i18n?
body: <p>Not that adding a require is a big deal but the <a href="http://nodemanual.org/latest/js_doc/Number.html#Number.toLocaleString" rel="nofollow">node docs suggest that you don't need it:</a> </p>
  
  <pre><code>// from the docs: 
  var number = 3500;
  console.log(number.toLocaleString()); // Displays "3,500" in English locale
  </code></pre>
  
  <p>Except that doesn't happen: </p>
  
  <pre><code>$ node
  &gt; var n = 1238909880
  undefined
  &gt; n.toLocaleString() 
  '1238909880'
  &gt; n.toLocaleString('en-US' )  // docs on node don't suggest this, but on MDN they do so...
  '1238909880'
  &gt; process.env.LANG
  'en_US.UTF-8'
  </code></pre>
  
  <p>Do I have to bring in i18n to get commas in my numbers? There's nothing about that on the nodejs docs for Number.toLocaleString. My <code>LANG</code> looks correct, as far as I know, which isn't far. Tried setting process.env.LANG to 'en-US' and the output didn't change. </p>