Firebase reference is empty after requiring new version
<p>The new <a href="https://firebase.google.com/docs/database/server/start#authenticate-with-admin-privileges" rel="nofollow">documentation</a> provides a straightforward method of initialising firebase, for example, this snipped comes directly from the <code>README.md</code> file:</p>

<blockquote>
  <p>Install the Firebase npm module:</p>
  
  <p><code>$ npm init</code><br>
  <code>$ npm install --save firebase</code></p>
  
  <p>In your code, you can access Firebase using:</p>
  
  <p><code>var firebase = require('firebase');</code><br>
  <code>var app = firebase.intializeApp({ ... });</code><br>
  <code>// ...</code></p>
</blockquote>

<p>But in my installation this is not working, as in, <code>firebase</code> is empty (<code>{}</code> when console logged).</p>

<p>There's another section in the documentation called <strong>Include only the features you need</strong>, which provides the following snippet:</p>

<pre><code>var firebase = require('firebase/app');
require('firebase/auth');
require('firebase/database');

var app = firebase.initializeApp({ ... });
// ...
</code></pre>

<p>This method works for me, so I'm wondering what could I be doing wrong in the first instance?</p>

<p><sub>
I'm using <code>browserify</code>, if that helps, but the docs state: The browser version is designed to be used with
a package bundler (e.g., <a href="http://browserify.org/" rel="nofollow">Browserify</a>,
<a href="https://webpack.github.io/" rel="nofollow">Webpack</a>).</sub></p>