<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8"/>
  </head>
  <body>
    <script>
      "use strict";

      window.big = (function makeBig(depth = 0) {
        let big = Array(5);
        big.fill(undefined);
        if (depth < 5) {
          big = big.map(_ => makeBig(depth + 1));
        }
        return big;
      }());
    </script>
  </body>
</html>
