app/redirect.html

<!DOCTYPE html>
<html>

<head>
    <title>GrabID Redirect</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<div id="errorMsg"></div>
<h3>
    For more information on why this redirect page exists, please look:
    <a href="https://tools.ietf.org/html/rfc6749#section-3.1.2.5">here</a>.
</h3>

<script type="text/javascript" src="../dist/bundle.js"></script>
<script>
    let returnUri = GrabID.getLoginReturnURI();

  if (window.location.search !== '') {
    try {
      GrabID.handleAuthorizationCodeFlowResponse()
      window.location.assign(returnUri)
    } catch (e) {
      let errObj = JSON.parse(e.message)
      let errorHtml = `<h2>${errObj.name}</h2><p>${errObj.message}</p>`
      errorHtml += `<p>Redirecting to ${returnUri} in 10 seconds.</p>`
      document.getElementById('errorMsg').innerHTML = errorHtml
      setTimeout(()=>{
        window.location.assign(returnUri)
      }, 10000)
    }

  } else if (window.location.hash !== '') {
    try {
      GrabID.handleImplicitFlowResponse()
      window.location.assign(returnUri)
    } catch (e) {
      let errObj = JSON.parse(e.message)
      let errorHtml = `<h2>${errObj.name}</h2><p>${errObj.message}</p>`
      errorHtml += `<p>Redirecting to ${returnUri} in 10 seconds.</p>`
      document.getElementById('errorMsg').innerHTML = errorHtml
      setTimeout(()=>{
        window.location.assign(returnUri)
      }, 10000)
    }
  }
</script>
</body>

</html>