Feature: Ability to force cors mode for some asset/data groups in service worker #47729

Which @angular/* package(s) are relevant/related to the feature request?

service-worker

Description

When using resources from a cross origin, by default fetch() is using cors mode but it's not the case when using <img> and other media element, or url() in CSS, browser defaults to no-cors and is able to use opaque response.
For HTML element, it's possible to force cors mode with the crossorigin attribute, but it's not possible in CSS.
Even when server is configured correctly for CORS, it will usually not responds any CORS headers when the request is made in no-cors mode.

In Service Worker, when handling a request to a different origin in no-cors mode, the response will be considered opaque and can't cached or at least not "safely" in a performance strategy because it will also cache error response (as stated in documentation).
Having the possibility to force cors mode for specific url patterns that we know are correctly configured and will handle CORS could ease the use of performance strategy and offline use-case when cross origin resources are involved.

It might be similar to #38907 (and PR #24510) but with ability to specify request option only on a group.

Proposed solution

Add an option for AssetGroup and DataGroup to force the group to be requested using cors mode when fetched.
It might be interesting in some case to also be able to pass a credentials option.

With an option specific on each group, it's really an opt-in for chosen url patterns, and it will not affects anything else.

Alternatives considered

I don't really see any. I've tried the alternative proposed by documentation, which is to use freshness strategy, but as SW will not differentiate valide opaque response and error, it will cache error and introduce unexpected behavior when offline. Also opaque response have negative impact on the estimation usage of the Storage API.