WelcomePage.js:101 TypeError: _firebase__WEBPACK_IMPORTED_MODULE_13__.default.ref is not a functio\ code example

Example: firebase.database is not a function

<script src="https://www.gstatic.com/firebasejs/7.24.0/firebase-auth.js"></script>
<script src="https://www.gstatic.com/firebasejs/7.24.0/firebase-database.js"></script>
// don't forget to change the "7.24.0" part of the url with the current version