docs/serviceWorker.js.liquid

---
permalink: /serviceWorker.js
---

// Useful resources:
// - https://eduardoboucas.com/blog/2015/06/04/supercharging-jekyll-with-a-serviceworker.html
// - https://jakearchibald.com/2014/offline-cookbook

var newCacheName = 'pouchdb-assets-cache-v{{ site.time }}';

var criticalAssets = [
  '{{ site.baseurl }}/offline.html',
  '{{ site.baseurl }}/static/css/pouchdb.min.css',
  '{{ site.baseurl }}/static/fonts/LatoLatin-Medium.woff2',
  '{{ site.baseurl }}/static/fonts//open-sans-v44-latin_latin-ext-regular.woff2',
  '{{ site.baseurl }}/static/fonts//open-sans-v44-latin_latin-ext-700.woff2'
];

{%- assign pages = collections.pages | where_exp: "page", "page.url != '/manifest.appcache'" -%}
{% assign guides = collections.guides %}

var pages = [
  {% for page in pages %}'{{ site.baseurl }}{{ page.url | replace:'index.html','' }}',
  {% endfor %}{% for page in guides %}'{{ site.baseurl }}{{ page.url | replace:'index.html','' }}'{% unless forloop.last %},{% endunless %}
  {% endfor %}];

var blogPosts = [{% for page in collections.posts %}
  '{{ site.baseurl }}{{ page.url | replace:'index.html','' }}',{% endfor %}
];

// Only cache the first blog page
var nonCriticalAssets =
  [
    '{{ site.baseurl }}/static/favicon.ico',
    '{{ site.baseurl }}/static/js/code.min.js',
    '{{ site.baseurl }}/static/js/jquery.min.js',
    '{{ site.baseurl }}/static/js/bootstrap.min.js',
    '{{ site.baseurl }}/static/js/pouchdb.min.js',
  ]
  .concat(pages)
  .filter(function (file) {
    return file.indexOf('/blog/page') === -1;
  })
  .concat(blogPosts.slice(0, 5)); // Let's only cache the first five by default

self.addEventListener('install', function (event) {
  event.waitUntil(
    caches.open(newCacheName)
      .then(function (cache) {
        cache.addAll(nonCriticalAssets);
        // Only return the criticalAssets to waitUntil
        // This will allow the noncritical assets to fail
        return cache.addAll(criticalAssets);
      })
      .then(function () {
        return self.skipWaiting();
      })
  );
});

self.addEventListener('activate', function (event) {
  // remove caches beginning "pouchdb-" that aren't the new cache
  event.waitUntil(
    caches.keys()
      .then(function (cacheNames) {
        return Promise.all(
          cacheNames.map(function (cacheName) {
            if (!/^pouchdb-/.test(cacheName)) {
              return;
            }
            if (newCacheName !== cacheName) {
              return caches.delete(cacheName);
            }
          })
        );
      })
      .then(function () {
        return self.clients.claim();
      })
  );
});

self.addEventListener('fetch', function (event) {
  // Ignore POST etc, which will happen when using PouchDB
  // in the browser console
  if (event.request.method === "GET") {
    // Ignore requests from browser extensions etc
    if ((event.request.url.indexOf('http') === 0)) {
      // Try the cache, if it's not in there try the network, then cache that response
      // if that network request fails show the offline.html page.
      event.respondWith(
        caches.open(newCacheName).then(function (cache) {
          return cache.match(event.request).then(function (response) {
            return response || fetch(event.request).then(function (response) {
              cache.put(event.request, response.clone());
              return response;
            }).catch(function () {
              return cache.match('{{ site.baseurl }}/offline.html');
            });
          });
      })
      );
    }
  }
});