roadamp/web/static/sw.js

'use strict';

const CACHE = 'roadamp-v1';
const SHELL = ['/', '/app.js', '/style.css', '/manifest.json', '/icon.svg'];

self.addEventListener('install', e => {
  e.waitUntil(
    caches.open(CACHE)
      .then(c => c.addAll(SHELL))
      .then(() => self.skipWaiting())
  );
});

self.addEventListener('activate', e => {
  e.waitUntil(
    caches.keys()
      .then(keys => Promise.all(
        keys.filter(k => k !== CACHE).map(k => caches.delete(k))
      ))
      .then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', e => {
  const url = new URL(e.request.url);
  // Pass through API calls and WebSocket upgrades uncached.
  if (url.pathname.startsWith('/api/') || url.pathname === '/ws') return;

  e.respondWith(
    caches.match(e.request).then(cached => {
      if (cached) return cached;
      return fetch(e.request).then(res => {
        const clone = res.clone();
        caches.open(CACHE).then(c => c.put(e.request, clone));
        return res;
      });
    })
  );
});