title: Launch-time initialization in Next.js static/exported site
body: <p>I'm trying to use Next to power an Electron app. <a href="https://github.com/leo/electron-next" rel="nofollow noreferrer">electron-next</a> uses Next's static site mode for its production build, which calls <code>getInitialProps</code> at build-time, rather than launch-time.</p>
  
  <p><strong>start.js</strong> (initially rendered page)</p>
  
  <pre><code>import Link from 'next/link'
  
  export default function Start({date}) {
    return (
      &lt;div&gt;
        &lt;div&gt;Date is {date}&lt;/div&gt; {/* &lt;- will always be the build time */}
        &lt;Link href="/about"&gt;
          &lt;a&gt;Take me to the About page&lt;/a&gt;
        &lt;/Link&gt;
      &lt;/div&gt;
    )
  }
  
  Start.getInitialProps = () =&gt; {
    return {
      date: "" + new Date()
    }
  }
  </code></pre>
  
  <p>Interestingly, using <code>Link</code> to navigate elsewhere does, in fact, result in a dynamic <code>getInitialProps</code> call.</p>
  
  <p><strong>about.js</strong></p>
  
  <pre><code>import Link from 'next/link'
  
  export default function About({date}) {
    return (
      &lt;div&gt;
        &lt;div&gt;Date is {date}&lt;/div&gt; {/* &lt;- will be the time the link was clicked */}
        &lt;div&gt;Important info about this app&lt;/div&gt;
      &lt;/div&gt;
    )
  }
  
  About.getInitialProps = () =&gt; {
    return {
      date: "" + new Date()
    }
  }
  </code></pre>
  
  <p>Is there a non-hacky way to get dynamic behavior for the initial route? I imagine this would have plenty of use cases in static sites, too.</p>