sw.js

---
---

var CACHE_NAME = '{{site.time}}';
var urlsToCache = [
    '/',
    '/assets/img/avatar.jpg',
    '/assets/css/site.css',
    '/assets/js/blog.min.js'
];
var blackList = [
    /google-analytics.com.*collect/,
    /^chrome-extension:\/\//
];

self.addEventListener('install', function (event) {
    event.waitUntil(caches.open(CACHE_NAME).then(function (cache) {
        return cache.addAll(urlsToCache);
    }));
});

self.addEventListener('activate', function (event) {
    event.waitUntil(caches.keys().then(function (cacheNames) {
        return Promise.all(cacheNames.map(function (cacheName) {
            if (cacheName !== CACHE_NAME) {
                return caches.delete(cacheName);
            }
        }));
    }));
});

self.addEventListener('fetch', function (event) {
    if (
        event.request.cache === 'only-if-cached' && event.request.mode !== 'same-origin'
    ) return cache(event.request);
    if (
        event.request.method !== 'GET' ||
        blackList.some(function (regex) {
            return regex.exec(event.request.url);
        })
    ) return network(event.request);
    var pn = networkAndSave(event.request);
    event.respondWith(cache(event.request).then(function (res) {
        return res || pn;
    }).catch(function () {
        return pn;
    }));
});

function cache (req) {
    return caches.open(CACHE_NAME).then(cache => cache.match(req.clone()));
}

function networkAndSave (req) {
    return network(req).then(function (res) {
        if (validate(res)) save(req.clone(), res.clone());
        return res;
    });
}

function network (req) {
    return fetch(req.clone());
}

function save (key, val) {
    return caches.open(CACHE_NAME).then(function (cache) {
        cache.put(key, val);
    });
}

function validate (res) {
    if (res && res.type === 'basic' && res.status !== 200) return false;
    return true;
}