title: Angular2 equivalent of angular.isArray
body: <p>Im playing around with NG2 and I am looking for the equivalent of <code>angular.isArray</code>.</p>
  
  <p>Yes, I tried to google it but no luck. Im probably thinking about this problem.</p>
  
  <p>The method I try to use in my ng2-app is this:</p>
  
  <pre><code>function periodsFormat(dates, func) {
    if (!angular.isArray(dates)) { return func(dates); }
    return dates.map(func).join('-');
  }
  </code></pre>
  
  <p>Surely it should work if I manage to replace <code>(!angular.isArray...</code> with something NG2-ish. Thank you!</p>
  
  <p>Update:</p>
  
  <p>Thank you both, I ended doing this:</p>
  
  <pre><code>function periodsFormat(dates, func) {
    if (!Array.isArray(dates)) { return func(dates); }
    return dates.map(func).join('-');
  }
  </code></pre>