gistfile1.js

/*jslint strict:global*/
/*global self, fetch, caches, console, Promise, Request*/
"use strict";

var CACHE_NAME_PREFIX = "ru~";
var CACHE_NAME = "ru~20180818T075107Z";

var URLS_TO_CACHE = "./;js.js?20180818T075107Z;css.css?20180818T075107";

self.addEventListener("install", function (event) {
  console.log("install", CACHE_NAME);
  event.waitUntil(caches.open(CACHE_NAME).then(function (cache) {
    return Promise.all(URLS_TO_CACHE.split(";").map(function (requestURL) {
      var request = new Request(requestURL);
      // I have added {cache: "no-cache"} option later.
      return fetch(request.clone()).then(function (response) {
        if (response.status >= 200 && response.status <= 299 && response.type === "basic") {
          return cache.put(request, response.clone());
        }
        return Promise.reject(new Error());
      });
    }));
  }));
});

self.addEventListener("activate", function (event) {
  console.log("activate", CACHE_NAME);
  event.waitUntil(caches.keys().then(function (cacheNames) {
    return Promise.all(cacheNames.map(function (cacheName) {
      if (cacheName.slice(0, CACHE_NAME_PREFIX.length) !== CACHE_NAME_PREFIX) {
        return undefined;
      }
      if (cacheName === CACHE_NAME) {
        return undefined;
      }
      return caches["delete"](cacheName);
    }));
  }));
});

self.addEventListener("fetch", function (event) {
  var request = event.request;
  var requestURL = request.url;
  event.respondWith(caches.open(CACHE_NAME).then(function (cache) {
    return cache.match(request).then(function (response) {
      if (response != undefined) {
        console.log("cache.match", CACHE_NAME, requestURL);
        return response;
      }
      return fetch(request.clone());
    });
  }));
});