fix: prefetch hook on lazy engine

addon/initializers/prefetch.js

@@ -1,13 +1,12 @@
 import Route from '@ember/routing/route';
 import RouteMixin from 'ember-prefetch/mixins/route';
+import { gte } from 'ember-compatibility-helpers';
 
-let hasInitialized = false;
+Route.reopen(RouteMixin);
 
-export function initialize() {
-  if (!hasInitialized) {
-    hasInitialized = true;
-
-    Route.reopen(RouteMixin);
+export function initialize(application) {
+  if (gte('3.6.0')) {
+    application.inject('route:application', '__prefetch', 'service:prefetch');
   }
 }
 

addon/instance-initializers/prefetch.js

@@ -3,9 +3,7 @@ import { resolve } from 'rsvp';
 import { gte } from 'ember-compatibility-helpers';
 
 export function initialize(instance) {
-  if (gte('3.6.0')) {
-    instance.inject('route:application', '__prefetch', 'service:prefetch');
-  } else {
+  if (!gte('3.6.0')) {
     // Delete all of this in the Ember 3.8 LTS and rev major
     const ROUTER_NAME = 'router:main';
     const router = instance.lookup(ROUTER_NAME);

addon/services/prefetch.js

@@ -1,7 +1,6 @@
 import Service, { inject as service } from '@ember/service';
-import { schedule } from '@ember/runloop';
 import { createPrefetchChangeSet } from '../-private/diff-route-info';
-import RSVP from 'rsvp';
+import { Promise, all } from 'rsvp';
 import { gte } from 'ember-compatibility-helpers';
 
 let PrefetchService;
@@ -13,23 +12,24 @@ if (gte('3.6.0')) {
     router: service('router'),
     init() {
       this._super(...arguments);
-      let privateRouter = this.router._router._routerMicrolib;
       let seenRoutes = new WeakMap();
 
       this.router.on('routeWillChange', transition => {
         if (transition.to && substatesRegex.test(transition.to.name)) {
           return;
         }
 
-        schedule('actions', () => {
+        let routePromises = transition.routeInfos.map((info) => info._routePromise);
+        all(routePromises).then(() => {
           if (!this.isDestroying && !this.isDestroyed) {
+            let privateRouter = this.router._router._routerMicrolib;
             let changeSet = createPrefetchChangeSet(privateRouter, transition);
             if (changeSet.shouldCall) {
               for (let i = 0; i < changeSet.for.length; i++) {
                 let { route, fullParams } = changeSet.for[i];
                 if (seenRoutes.has(route)) continue;
 
-                route._prefetched = new RSVP.Promise(r => {
+                route._prefetched = new Promise(r => {
                   return r(route.prefetch(fullParams, transition));
                 });
                 seenRoutes.set(route, true);

testem.js

@@ -9,7 +9,6 @@ module.exports = {
         // --no-sandbox is needed when running Chrome inside a container
         process.env.CI ? '--no-sandbox' : null,
         '--headless',
-        '--disable-gpu',
         '--disable-dev-shm-usage',
         '--disable-software-rasterizer',
         '--mute-audio',

tests/acceptance/engine-test.js

@@ -23,7 +23,6 @@ module('lazy engine loading', function(hooks) {
     );
     this.owner.register('template:application', hbs`{{outlet}}`);
     this.owner.register('controller:application', Controller.extend());
-    debugger;
     AppRouter.map(function() {
       this.mount('blog');
     });