Gracefully handle missing code bundles (no internet or app updated)

[incognitojam]

We get errors like this when a client loads the site and later, after an update has been deployed to the server, tries to access a different page which requires loading a code bundle. The client requests the JS bundle from the server, but the new deployment doesn't serve this file anymore (each bundle has a hash in the file name), so the client errors.

ChunkLoadError: Loading chunk 3 failed.
(missing: https://connect.comma.ai/static/js/3.ff182016.chunk.js)
  at None (https://connect.comma.ai/:1:4730)
  at _callee16$ (qr-scanner.ts:633:16)
  at tryCatch (None:7:30)
  at key (None:7:30)
  at Promise ([native code])

This error can also happen if the user goes offline after they load the page originally.

We should do at least one of the following things:

• Serve old bundles for longer (maybe at least a week after each release)
• Request a reload when an update is detected
  • Some apps show a prompt to the user and we can reload the page when they confirm
• Catch the error
  • Perhaps show a fallback notice that the app is out of date
  • Reload the page

Related: https://stackoverflow.com/a/62038528/1908134

[sentry-io]

Sentry issue: CONNECT-1BH

[incognitojam]

This is partially fixed by #392, but the update available/ready state should be surfaced somewhere.