title: How to check if variable is a tuple in TypeScript
body: <p>I am trying to see if a variable passed to a function (that can be either an array of numbers or an array of tuples) is the array of tuples.</p>
  
  <pre><code>function (times: Array&lt;number&gt; | Array&lt;[number, number]&gt;) {
      if (times[0] instanceof [number, number]) {
          console.log("Its the tuple one!");
      }
  }
  </code></pre>
  
  <p>The above code doesn't work though and I've also tried <code>if (times[0] instanceof tuple))</code> but that doesn't work either. How can this be done?</p>
  
  <p>Thanks!</p>