Add worker_support info for CacheStorage

[hamishwillee]

CacheStorage is defined in the service worker spec but also works in the main thread and other worker types. This PR updates CacheStorage information to have a worker_support key.

What I did was duplicate the top level support for CacheStorage as the key worker_support. My assumption being that worker support went in for the first version unless otherwise documented (seems reasonable because this is in the service worker spec)

There is a note indicating that for Chrome it became accessible through WorkerWindowScope (and window) in version 43. My assumption is therefore that this is a case where the class was available, but inaccessible. So I have updated the worker support information to 43 for that case.

There is also a note for FF on all methods: "notes": "Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.". I copied this to just mention service workers.

@ddbeck

• Does this make sense?
• The note about ESR versions appears on all methods. Is it necessary - ie propose to remove it except for the parent CacheStorege.

[hamishwillee]

@ddbeck Further, looking at Cache (which is used with CacheStorage) the BCD says support from chrome 43 but From 40 to 42, this was only available on service workers.

That's a bit confusing. It kind of indicates to me that perhaps the note for CacheStorage is incorrect "Accessible from WorkerGlobalScope from version 43." - and this should be from version 40 (with other corresponding changes).

Thoughts?

[ddbeck]

My first (possibly wrong!) impressions:

• We ought to remove the Accessible from notes outright. These notes basically say which api.{SomeInterface}.caches features exist. We have, for example, an api.WindowOrWorkerGlobalScope.caches feature that ought to cover these details (API moves might be appropriate on that feature, but not here).
• I'm not quite sure what "the class was available, but inaccessible" means. Does this mean that CacheStorage is only sometimes in the global scope and that's what these values reflect?

[hamishwillee]

@ddbeck Thanks very much. So I have updated in line with your comments and my interpretation. Essentially that CacheStorage was supported in Chrome in service workers from 40, and other workers/main thread from version 43.

This is heavily implied by the Cache docs which explicitly state that.

[hamishwillee]

PS For Cache the BCD currently says we have version-added 43 and note "From 40 to 42, this was only available on service workers.". Our previous discussion was that the version should reflect when the first worker was added and the note reflect any variation.

So propose for Cache:

• change version-added to 40 on the top level docs and leave the note.
• Then add worker_support that duplicates this pattern

Make sense?

[ddbeck]

Overall, I'm really happy with this. I think it's telling a much clearer story! And the proposal for Cache makes sense. I think we just need one more pass on this. Suggestions in line comments.

[hamishwillee]

Hi @ddbeck
Thanks, works for me. All your suggestions addressed (I think). I'll look at Cache once this is accepted.

[ddbeck]

Thank you, @hamishwillee! 🎉

[hamishwillee]

A win! Thanks @ddbeck