Fix service worker serving from cache (#56)

* Fix service worker serving from cache

* Fix SW test

Author: kevhender

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-storefront",
-  "version": "7.7.0",
+  "version": "7.7.1",
   "description": "Build and deploy e-commerce progressive web apps (PWAs) in record time.",
   "module": "./index.js",
   "license": "Apache-2.0",

service-worker/bootstrap.js

@@ -252,6 +252,10 @@ self.addEventListener('fetch', event => {
   event.respondWith(
     (async function() {
       try {
+        const cacheResponse = await caches.match(event.request)
+        if (cacheResponse) {
+          return cacheResponse
+        }
         return await fetch(event.request)
       } finally {
         if (toResume.size) {

test/bootstrap.test.js

@@ -1,5 +1,4 @@
 import makeServiceWorkerEnv from 'service-worker-mock'
-import makeFetchMock from 'service-worker-mock/fetch'
 
 let sw
 
@@ -15,7 +14,7 @@ describe('bootstrap', () => {
       expiration: { ExpirationPlugin: jest.fn() },
       routing: { registerRoute: jest.fn() },
     }
-    Object.assign(global, serviceWorkerEnv, makeFetchMock())
+    Object.assign(global, serviceWorkerEnv)
     jest.resetModules()
     sw = require('../service-worker/bootstrap')
   })
@@ -90,7 +89,7 @@ describe('bootstrap', () => {
     it('should resume prefetches when non-prefetch fetch is done', async () => {
       const toResume = sw.__get__('toResume')
       toResume.add([{ path: '', apiVersion: 'v1' }])
-      await self.trigger('fetch')
+      await self.trigger('fetch', '')
       expect(toResume.size).toEqual(0)
     })