<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta http-equiv="x-ua-compatible" content="ie=edge">

    <title>react-calendar-heatmap</title>

    <link rel="stylesheet" href="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/css/bootstrap.css" />
    <link rel="stylesheet" href="styles.css" />

    <style>
      /* bootstrap overrides */
      a {
        color: #3e98c7;
      }
      a:hover {
        text-decoration: none;
      }
    </style>
  </head>
  <body>
    <div id="demo"></div>
    <script src="index.js" type="text/javascript"></script>

    <!-- bootstrap tooltips -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/tether/1.3.2/js/tether.min.js"></script>
    <script src="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/js/bootstrap.js"></script>
    <script>
      $(document).ready(function() {
        $('[data-toggle="tooltip"]').tooltip();
      });
    </script>
  </body>
</html>

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta http-equiv="x-ua-compatible" content="ie=edge">

    <title>react-calendar-heatmap</title>

    <link rel="stylesheet" href="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/css/bootstrap.css" />
    <link rel="stylesheet" href="styles.css" />

    <style>
      /* bootstrap overrides */
      a {
        color: #3e98c7;
      }
      a:hover {
        text-decoration: none;
      }
    </style>
  </head>
  <body>
    <div id="demo"></div>
    <script src="index.js" type="text/javascript"></script>

    <!-- bootstrap tooltips -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/tether/1.3.2/js/tether.min.js"></script>
    <script src="https://cdn.rawgit.com/twbs/bootstrap/v4-dev/dist/js/bootstrap.bundle.min.js"></script>
    <script>
      $(document).ready(function() {
        $('[data-toggle="tooltip"]').tooltip({
          title: function() {
            return $(this)[0].textContent;
          }
        });
      });
    </script>
  </body>
</html>

Fix that tooltip doesn't work on demo page
Fix that tooltip doesn't work on demo page
