From c530c5d3176f7281780dce146c4b459043ac684b Mon Sep 17 00:00:00 2001
From: Ward Bell <wardbell@hotmail.com>
Date: Mon, 3 Apr 2017 11:48:46 -0600
Subject: [PATCH] fix(aio): when browser lacks service worker, disable sw
 feature

---
 aio/src/app/sw-updates/sw-updates.service.ts | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/aio/src/app/sw-updates/sw-updates.service.ts b/aio/src/app/sw-updates/sw-updates.service.ts
index 60a9ef1fcb..86a75037f3 100644
--- a/aio/src/app/sw-updates/sw-updates.service.ts
+++ b/aio/src/app/sw-updates/sw-updates.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, OnDestroy } from '@angular/core';
+import { Injectable, Injector, OnDestroy } from '@angular/core';
 import { NgServiceWorker } from '@angular/service-worker';
 import { Observable } from 'rxjs/Observable';
 import { ReplaySubject } from 'rxjs/ReplaySubject';
@@ -36,9 +36,13 @@ export class SwUpdatesService implements OnDestroy {
   private onDestroy = new Subject();
   private checkForUpdateSubj = new Subject();
   private isUpdateAvailableSubj = new ReplaySubject<boolean>(1);
+  private sw: NgServiceWorker | NullServiceWorker = null;
   isUpdateAvailable = this.isUpdateAvailableSubj.distinctUntilChanged();
+  isServiceWorkAvailable = !!navigator['serviceWorker'];
+
+  constructor(injector: Injector) {
+    this.sw = this.isServiceWorkAvailable ? injector.get(NgServiceWorker) : new NullServiceWorker();
 
-  constructor(private sw: NgServiceWorker) {
     this.checkForUpdateSubj
         .debounceTime(this.checkInterval)
         .takeUntil(this.onDestroy)
@@ -74,3 +78,8 @@ export class SwUpdatesService implements OnDestroy {
         .subscribe(v => this.isUpdateAvailableSubj.next(v));
   }
 }
+
+class NullServiceWorker {
+  checkForUpdate() { return Observable.of(false); }
+  activateUpdate(version: string) { return Observable.of(false); }
+}