[1.2.2] Some assets not compiled until ionic serve stopped then run again

[brettdorrans]

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Short description of the problem:

Using 1.2.2 of ionic-app-scripts and ionic serve - occasionally components will not be compiled. e.g., if I make a change to a Provider, the build completes and reloads the browser, but the changes are not reflected (or intermittently reflected, sometimes I can refresh the page and they'll appear, but after another refresh will be gone again).

What behavior are you expecting?

All changes to be reflected and persistent after build completes.

Steps to reproduce:

1. Using 'ionic serve' on ionic-app-scripts 1.2.2, save file and wait for build process to complete.
2. Occasionally/intermittently your changes will not be reflected.
3. Refresh page manually and changes will sometimes appear, but subsequent refreshes may make them disappear again. I can't reliably reproduce this.

Which @ionic/app-scripts version are you using?

Ionic Framework Version: 2.2.0
Ionic CLI Version: 2.2.1
Ionic App Lib Version: 2.2.0
Ionic App Scripts Version: 1.2.2
ios-deploy version: 1.9.0
ios-sim version: 5.0.13
OS: macOS Sierra
Node Version: v6.9.1
Xcode version: Xcode 8.2.1 Build version 8C1002

Other information: (e.g. stacktraces, related issues, suggestions how to fix, stackoverflow links, forum links, etc)
Is probably related to #825

[brettdorrans]

Had initially reported this on 1.2.1, upgraded to 1.2.2 and issue persists.

[brettdorrans]

Issue also present on nightly 1.2.2-201703281515

[brettdorrans]

This is related to the --iscordovaserve flag on the ionic:serve script.

Removing this removes this bug, but then renders the above flag useless.

Scrach above, still occurs with standard ionic:serve.

[brettdorrans]

Issue persists in 1.2.5

[brettdorrans]

This was actually caused by the default service-worker being enabled.

Commenting out from index.html and deregistering via chrome://serviceworker-internals/ fixed the issue.