title: How do I declare a return type of a tuple of two numbers?
body: <p>When I declare a function as </p>
  
  <pre><code>const coordinates = (id: number): ([number, number]) =&gt; {
  </code></pre>
  
  <p>the error I get is <code>[ts] Duplicate identifier 'number'.</code></p>
  
  <p>If I omit type signature for return value, then it infers it as <code>number[]</code> </p>