fix(docs-infra): print info to help debugging SW cache issue (#41106)
From time to time, an angular.io page fails to load due to requesting a
file that cannot be found neither on the server nor in the cache. We
believe this is caused by the browser's partially clearing a cache.
See #28114 for more details.
Some time ago, we introduced [SwUpdate#unrecoverable][1] to help work
around this issue by [reloading the page][2] when such an error is
detected.
However, this issue still pops up occasionally (for example, #41073).
In an attempt to help diagnose the issue, this commit prints more info
regarding the SW state and cache content when this error occurs. It will
result in something like the following being printed to the console:
```
ServiceWorker: activated
Cache: ngsw:/:db:control (2 entries)
- https://angular.io/assignments: {"f5f02035-ee1f-463c-946c-e8b85badca25":"5c95f89a85255a6fefb4045a20f751ef32b2f3a4"}
- https://angular.io/latest: {"latest":"5c95f89a85255a6fefb4045a20f751ef32b2f3a4"}
Cache: ngsw:/:5c95f89a85255a6fefb4045a20f751ef32b2f3a4:assets:app-shell:cache (24 entries)
- https://angular.io/0-es2015.867022f8bb092ae1efb1.worker.js
- https://angular.io/announcement-bar-announcement-bar-module-es2015.1b5b762c9c8837c770f8.js
- https://angular.io/api-api-list-module-es2015.40a43cd22f50f64d63bb.js
...
Cache: ngsw:/:db:ngsw:/:5c95f89a85255a6fefb4045a20f751ef32b2f3a4:assets:app-shell:meta (1 entries)
- https://angular.io/https://fonts.gstatic.com/s/robotomono/v13/L0x5DF4xlVMF-BfR8bXMIjhLq3-cXbKD.woff2:
{"ts":1615031956601,"used":true}
If you see this error, please report an issue at https://github.com/angular/angular/issues/new?template=3-docs-bug.md
including the above logs.
```
NOTE:
This change increases the main bundle by 1649B (0.37%), but it can be
reverted as soon as we gather enough info to diagnose the issue.
[1]: https://angular.io/api/service-worker/SwUpdate#unrecoverable
[2]: https://github.com/angular/angular/blob/c676ec1ce5d586d4bc46/aio/src/app/sw-updates/sw-updates.service.ts#L55-L61
PR Close #41106
f281310d39