Cache gtm.js runtime caching

packages/workbox-google-analytics/initialize.mjs

@@ -21,6 +21,7 @@ import {
   GTM_HOST,
   ANALYTICS_JS_PATH,
   GTAG_JS_PATH,
+  GTM_JS_PATH,
   COLLECT_PATHS_REGEX,
 } from './utils/constants.mjs';
 import './_version.mjs';
@@ -157,6 +158,22 @@ const createGtagJsRoute = (cacheName) => {
   return new Route(match, handler, 'GET');
 };
 
+/**
+ * Creates a route with a network first strategy for the gtm.js script.
+ *
+ * @param {string} cacheName
+ * @return {Route} The created route.
+ *
+ * @private
+ */
+const createGtmJsRoute = (cacheName) => {
+  const match = ({url}) => url.hostname === GTM_HOST &&
+      url.pathname === GTM_JS_PATH;
+  const handler = new NetworkFirst({cacheName});
+
+  return new Route(match, handler, 'GET');
+};
+
 /**
  * @param {Object=} [options]
  * @param {Object} [options.cacheName] The cache name to store and retrieve
@@ -182,6 +199,7 @@ const initialize = (options = {}) => {
   });
 
   const routes = [
+    createGtmJsRoute(cacheName),
     createAnalyticsJsRoute(cacheName),
     createGtagJsRoute(cacheName),
     ...createCollectRoutes(queuePlugin),

packages/workbox-google-analytics/utils/constants.mjs

@@ -14,6 +14,7 @@ export const GOOGLE_ANALYTICS_HOST = 'www.google-analytics.com';
 export const GTM_HOST = 'www.googletagmanager.com';
 export const ANALYTICS_JS_PATH = '/analytics.js';
 export const GTAG_JS_PATH = '/gtag/js';
+export const GTM_JS_PATH = '/gtm.js';
 export const COLLECT_DEFAULT_PATH = '/collect';
 
 // This RegExp matches all known Measurement Protocol single-hit collect

test/workbox-google-analytics/integration/basic-example.js

@@ -10,6 +10,8 @@ const expect = require('chai').expect;
 const qs = require('qs');
 const {By} = require('selenium-webdriver');
 const activateAndControlSW = require('../../../infra/testing/activate-and-control');
+const waitUntil = require('../../../infra/testing/wait-until');
+
 
 describe(`[workbox-google-analytics] Load and use Google Analytics`, function() {
   const driver = global.__workbox.webdriver;
@@ -101,6 +103,7 @@ describe(`[workbox-google-analytics] Load and use Google Analytics`, function()
         event_callback: () => done(),
       });
     });
+    // This request should not match GA routes, so it shouldn't be replayed.
     await driver.executeAsyncScript((done) => {
       fetch('https://httpbin.org/get').then(() => done());
     });
@@ -112,17 +115,17 @@ describe(`[workbox-google-analytics] Load and use Google Analytics`, function()
     });
     expect(requests).to.have.lengthOf(0);
 
-    // Uncheck the "simulate offline" checkbox and then trigger a sync.
+    // Uncheck the "simulate offline" checkbox, which should let queued
+    // requests start to replay successfully.
     await simulateOfflineEl.click();
-    await driver.executeAsyncScript(messageSW, {
-      action: 'dispatch-sync-event',
-    });
 
-    // Ensure only 2 requests have replayed, since only 2 of them were to GA.
-    requests = await driver.executeAsyncScript(messageSW, {
-      action: 'get-spied-requests',
-    });
-    expect(requests).to.have.lengthOf(2);
+    // Wait until all expected requests have replayed.
+    await waitUntil(async () => {
+      requests = await driver.executeAsyncScript(messageSW, {
+        action: 'get-spied-requests',
+      });
+      return requests.length === 2;
+    }, 25, 200);
 
     // Parse the request bodies to set the params as an object and convert the
     // qt param to a number.
@@ -132,7 +135,6 @@ describe(`[workbox-google-analytics] Load and use Google Analytics`, function()
       request.originalTime = request.timestamp - request.params.qt;
     }
 
-
     expect(requests[0].params.ea).to.equal('beacon');
     expect(requests[1].params.ea).to.equal('pixel');
 

test/workbox-google-analytics/node/test-index.mjs

@@ -19,6 +19,7 @@ import {
   GTM_HOST,
   ANALYTICS_JS_PATH,
   GTAG_JS_PATH,
+  GTM_JS_PATH,
 } from '../../../packages/workbox-google-analytics/utils/constants.mjs';
 
 const PAYLOAD = 'v=1&t=pageview&tid=UA-12345-1&cid=1&dp=%2F';
@@ -73,6 +74,21 @@ describe(`[workbox-google-analytics] initialize`, function() {
     expect(NetworkFirst.prototype.handle.calledOnce).to.be.true;
   });
 
+  it(`should register a handler to cache the gtm.js script`, function() {
+    sandbox.spy(NetworkFirst.prototype, 'handle');
+
+    initialize();
+
+    self.dispatchEvent(new FetchEvent('fetch', {
+      request: new Request(
+          `https://${GTM_HOST}${GTM_JS_PATH}?id=GTM-XXXX`, {
+            mode: 'no-cors',
+          }),
+    }));
+
+    expect(NetworkFirst.prototype.handle.calledOnce).to.be.true;
+  });
+
   it(`should accept an optional cache name`, async function() {
     initialize({cacheName: 'foobar'});
 

test/workbox-google-analytics/static/basic-example/sw.js

@@ -11,14 +11,21 @@ importScripts('/infra/testing/comlink/sw-interface.js');
 
 workbox.setConfig({modulePathPrefix: '/__WORKBOX/buildFile/'});
 
+const sleep = async (ms) => {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+};
+
 // Spy on .fetch() calls from inside the service worker.
 // If `simulateOffline` is set to true, throw a network error.
 let simulateOffline = false;
 let spiedRequests = [];
 const originalFetch = self.fetch;
 self.fetch = async (...args) => {
   if (simulateOffline) {
-    throw Response.error();
+    // Simulate network latency, so the sync event doesn't just fire
+    // in an endless loop.
+    await sleep(100);
+    throw new Error('Simulated network error');
   }
   const clone = args[0] instanceof Request ?
     args[0].clone() : new Request(args[0]);
@@ -45,20 +52,6 @@ self.addEventListener('message', (evt) => {
     case 'get-spied-requests':
       evt.ports[0].postMessage(spiedRequests);
       break;
-    case 'dispatch-sync-event':
-      {
-      // Override `.waitUntil` so we can signal when the sync is done.
-        const originalSyncEventWaitUntil = SyncEvent.prototype.waitUntil;
-        SyncEvent.prototype.waitUntil = (promise) => {
-          return promise.then(() => evt.ports[0].postMessage(null));
-        };
-
-        self.dispatchEvent(new SyncEvent('sync', {
-          tag: 'workbox-background-sync:workbox-google-analytics',
-        }));
-        SyncEvent.prototype.waitUntil = originalSyncEventWaitUntil;
-      }
-      break;
   }
 });