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<h2>Hosting an <a href="https://immutablewebapps.org">Immutable Web App</a> with <a href="https://www.npmjs.com/">npm</a>,

<a href="https://unpkg.com/#/">UNPKG</a>, and <a href="https://pages.github.com/">GitHub Pages</a></h2>

<p>Immutable Web Apps are composed of two concepts:</p>

<ul>

<li><b>Immutable Assets:</b> Static assets (javascript, CSS, images) that do not contain any

environment-specific

configuration and are hosted at a permanent, versioned,

long-term browser cached location.</li>

<br />

<li><b>Deployment Manifest:</b> An <code>index.html</code> that is unique to the environment and not cached by

the

browser. It contains environment-specific configuration, references to the versioned immutable assets, and

meta

data.</li>

</ul>

<p>Using a combination of npm, UNPKG, and Github Pages covers nearly all of these requirements!</p>

<ul>

<li><b><a href="https://www.npmjs.com/">npm</a>:</b> The software registry stores the the static assets in

versioned, immutable packages. <i>Perfect for managing the immutable assets!</i></li>

<br />

<li><b><a href="https://unpkg.com/#/">UNPKG</a>:</b> The CDN makes all assets of the packages on npm

addressable

over https

and globally available. <i>Perfect for delivering the immutable assets!</i></li>

<br />

<li><b><a href="https://pages.github.com/">GitHub Pages</a>:</b> This static hosting site supports easy

configuration of DNS and HTTPS, has great integration with GitHub (obviously), and has a short TTL for

browser caching. <i>Perfect for serving the deployment manifest!</i></li>

</ul>

<h2><i>This Immutable Web App is hosted using npm, UNPKG, and GitHub Pages!</i></h2>

<h3>Project Structure</h3>

<p>The git repository <a href="https://github.com/ImmutableWebApps/unpkg-immutable-example">unpkg-immutable-example</a>

is split into two critical branches:</p>

<ul>

<li><a href="https://github.com/ImmutableWebApps/unpkg-immutable-example/tree/default"><code>default</code></a>

is where the Angular project is maintained. It was generated from Angular CLI and is maintained like

any other static web application.</li>

<br />

<li><a href="https://github.com/ImmutableWebApps/unpkg-immutable-example/tree/master"><code>master</code></a>

is

configured to serve the GitHub Pages site. It only contains a single file <a href="https://github.com/ImmutableWebApps/unpkg-immutable-example/blob/master/404.html"><code>404.html</code></a>.

This single file is <a href="https://help.github.com/articles/creating-a-custom-404-page-for-your-github-pages-site/">served

for every request</a> made to the GitHub Pages site.</li>

</ul>

<h3>Project Lifecycle</h3>

<h4>Building</h4>

<p>Developing this web application is the same as any other single-page app node project. Features are built

and tested locally, commits and

pull requests advance the state of the codebase. When a stable version of the app is ready to be deployed,

the

assets are rendered to the <code>/dist</code> folder using <code>npm run build</code> and new version of

the

project is published to npm using <code>npm publish</code>. The assets become available on <a href="https://unpkg.com/@immutablewebapps/unpkg-immutable-example/">UNPKG</a>.</p>

<h4>Deploying</h4>

<p>With the new version of the assets available on UNPKG, an <i>atomic</i> deployment can be triggered by

switching to the <code>master</code> branch and updating <code>404.html</code> with the references to the

new project

assets and any changes to environment variables. Once the commit is is pushed to the GitHub repository,

GitHub Pages

deployment is triggered and the new version of the web application is available.</p>

<h2><i>Deployments!</i></h2>

<p>With our Immutable Web App hosted by npm/UNPKG and without any environment-specific configuration,

deployments

are cheap and reliable! Let's deploy <code>index.html</code> to wherever it is easiest to setup DNS and

HTTPS!</p>

<h3>Deploy to another Github Pages repository</h3>

<p><i>and let's change the version!</i></p>

<ul>

<li>Fork <a href="https://github.com/ImmutableWebApps/unpkg-immutable-deployment">unpkg-immutable-deployment</a></li>

<li><a href="https://help.github.com/articles/configuring-a-publishing-source-for-github-pages/">Configure

the

repo as a publishing source for Github Pages</a></li>

<li>Modify the <code>404.html</code> to point to a different version</li>

<li><a href="https://immutablewebapps.org/unpkg-immutable-deployment"><b><i>Deployed!</i></b></a></li>

</ul>

<h3>Deploy to Netlify</h3>

<p><i>and let's change some environment variables!</i></p>

<ul>

<li><code>git clone

https://github.com/ImmutableWebApps/unpkg-immutable-deployment</code></li>

<li><code>cd unpkg-immutable-deployment</code></li>

<li><a href="https://app.netlify.com/">Create a Netlify account</a></li>

<li>Run <code>npm i -g netlify-cli</code></li>

<li>Run <code>netlify login</code></li>

<li>Run <code>netlify deploy</code></li>

<li><a href="https://immutablewebapps.netlify.com"><b><i>Deployed!</i></b></a></li>

</ul>

<h3>Deploy Locally</h3>

<p><i>and configure it however you want! Try loading up some <a href="https://github.com/ImmutableWebApps/unpkg-immutable-example/releases">older

versions!</a></i></p>

<ul>

<li><code>git clone

https://github.com/ImmutableWebApps/unpkg-immutable-deployment.git</code></li>

<li><code>cd unpkg-immutable-deployment</code></li>

<li><code>npm i -g ecstatic</code></li>

<li><code>ecstatic</code> (<a href="https://www.npmjs.com/package/ecstatic">ecstatic</a> is a simple static

file server)</li>

<li><a href="http://0.0.0.0:8000"><b><i>Deployed!</i></b></a></li>

</ul>