Call into JSON-LD via its WebIDL API instead of calling algorithms directly

[jyasskin]

In the discussion at w3c/json-ld-api#580 (comment), @gkellogg says that specs should always use the JSON-LD API instead of calling directly into JSON-LD algorithms. data-cite="JSON-LD11-API seems to be a good search term in this spec to find places that need fixing.

[msporny]

Hmm, I'm not sure this is necessary. We've got upwards of 17 implementations at this point and none of them seem to have been tripped up by this not calling into the JSON-LD algorithms using the WebIDL interfaces. Additionally, given that browsers don't implement the WebIDL interfaces, and don't plan to (AFAIK), I'm not seeing the benefit of making this change.

Out of curiosity, exactly how should the text change to use the WebIDL API?

/cc @gkellogg @dlongley @BigBlueHat @davidlehn to get more opinions if there is something for us to do here.

[gkellogg]

The reason for this recommendation is that the algorithms make use of options set the API (e.g., compactArrays, documentLoader, processingMode, ...). That's not to say that you can't use the algorithms directly, but where they call for using the value (explicit or default) of an API option, you'll need to take a separate provision for this.

As long as dependent specs are cognizant of this (e.g., using xxx for documentLoader) it should be fine, but the algorithms to take advantage of the envelope the API method steps provide.