It's unclear why `import as` results in the aliases to be undefined.
Plain tsc seems to do the right thing and emits the correct code, so it
might be some kind of interaction in @angular/cli or webpack that are
causing the failure.
This should be investigated separately from the tsc update in
angular/angular. See angular/angular-cli#13212
PR Close#27536
AIO is currently using a beta version of @angular/service-worker.
Since that was implemented, the SW has been rewritten and released
as part of Angular 5.0.0. This commit updates AIO to use the latest
implementation, with an appropriate configuration file that caches
the various AIO assets in useful ways.
PR Close#19795
