Service Worker on Rails example

serviceworker.js

self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.open('mysite-dynamic').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;
        });
      });
    })
  );
});

serviceworker.rb

Rails.application.configure do
  config.serviceworker.routes.draw do
    # maps to asset named 'serviceworker.js' implicitly
    match "/serviceworker.js"
  end
end