CODE EXAMPLE FOR JAVASCRIPT

Uncaught TypeError: firebase_app__WEBPACK_IMPORTED_MODULE_4__.default.storage is not a function

I faced the same problem. In my case, I needed to include storage module besides Firebase core.

import firebase from 'firebase';
import 'firebase/storage';  // <----

firebase.initializeApp({
  ...
});
const storageRef = firebase.storage().ref();