New "pwalocalserve" mode to inject manifest and get service worker debugging

[kb-coder]

What problem does this feature solve?

Workbox will only add debugging when the NodeEnv is development (see GoogleChrome/workbox#1619 (comment)), but the cli-plugin-pwa does not give us a way to run the injected version of the pwa in a way that we can get debugging info because it only injects the manifest when NodeEnv is production (see https://github.com/vuejs/vue-cli/blob/dev/packages/%40vue/cli-plugin-pwa/index.js).

It would be helpful to support the following use cases:

1. Development mode with no manifest injection
2. Development mode (new "pwalocalserve") with manifest injection and debugging
3. Production mode manifest injection with no debugging.

Can we get a "pwalocalserve" that builds the PWA with the injected manifest and debugging so we can troubleshoot issues with custom service worker code?

What does the proposed API look like?

pwa-build": "vue-cli-service build --mode pwalocalserve",

[kb-coder]

I ended up forking the pwa plugin here: https://github.com/kb-coder/vue-cli-plugin-workbox-pwa

This uses workbox, InjectManifest, and sets up a pwalocalserve mode that runs in Node_Env='development' but allows us to run the pwa so we can debug the service worker. I also added some common features of a PWA:

• user based prompt when a new version of the service worker is available
• auto update of the service worker (for a landing page / login page).
  I would love to see this code incorporated back into Vue CLI.