title: Typescript: Can't index an array that is being returned from a function
body: <p>I want to index an array that is being constructed and returned from a function but I am given the error: </p>
  
  <pre><code>Element implicitly has an 'any' type because expression of type '3' can't be used to index type 'ArrFunc'.
    Property '3' does not exist on type 'ArrFunc'
  </code></pre>
  
  <p>This is the code I have recreated on Typescript playground to show my issue.</p>
  
  <pre><code>type ArrFunc = () =&gt; number[];
  const arrFunc:ArrFunc = () =&gt; [1, 2, 3, 4];
  
  console.log(arrFunc[3]);
  </code></pre>
  
  <p>I am unsure which "Element implicitly has an 'any' type." As far as I can tell, everything in the above example is pretty well defined.</p>
  
  <p>Thanks in advance!</p>