1. While on a different site, I turn offline mode on in the network tab.
2. I navigate to my web app, which is available offline thanks to the service worker.
3. I click some buttons that are supposed to register a Background Sync.
4. I turn offline mode off in the network tab.
5. Nothing happens.
6. I close browser, restart computer, try again with the steps that worked above, and no Background Syncs are ever triggered after this.
7. After I go to the Application tab, and unregister the service worker, and try again from a fresh installation, the first steps work, but the second set of steps keeps breaking the Background Sync

This leads me to believe the sync registration happens, but the service worker isn't listening anymore. And no matter what I do, like close the browser, refresh the page when online, wait a while, the service worker just won't listen to sync events anymore.

1. While on a different site, I turn offline mode on in the network tab.
2. I navigate to my web app, which is available offline thanks to the service worker.
3. I click some buttons that are supposed to register a Background Sync.
4. I turn offline mode off in the network tab.
5. Nothing happens.
6. After I go to the Application tab, and unregister the service worker, and try again from a fresh installation, the first steps work, but the second set of steps keeps breaking the Background Sync

This leads me to believe the sync registration happens, but the service worker isn't listening anymore. And no matter what I do, like close the browser tab, refresh the page when online, wait a while, the service worker just won't listen to sync events anymore.

##It works:

##It stops working: It stops working completely, even in the above scenario if I do the following:

##Steps that work:

##Steps that cause it to stop working: It stops working completely, even in the above scenario if I do the following:

#Update

When the code works, I used the following code to keep track of tags sent to registration:

navigator.serviceWorker.ready.then(function (reg) { console.log('before', reg.sync.getTags()); reg.sync.register('sync-tag'); console.log('after', reg.sync.getTags()); }).catch(function (e) { console.error(e, "System was unable to register for a sync"); }); 

When using the steps that work, I get

before: resolved to an empty array after: resolved to an array with one tag ['sync-tag'] 

When using the steps that cause it to stop working:

before: resolved to an array with one tag ['sync-tag'] after: resolved to the same array above 

This leads me to believe the sync registration happens, but the service worker isn't listening anymore. And no matter what I do, like close the browser, refresh the page when online, wait a while, the service worker just won't listen to sync events anymore.

I understand that is up to the browser to decide when to make the Background Sync, but I just don't understand why this isn't working. Unless the expected behavior is to expect the user to visit the web app when online, I think I'm getting something wrong.

Thank you for your patience, and any help understanding how to make Background Sync work will be appreciated.