[tidoust]

The constructor takes a VideoColorSpaceInit dictionary as input that does not have any required parameter. Quoting from the Web IDL spec, the input "must be specified as optional and have a default value provided. This is to encourage API designs that do not require authors to pass an empty dictionary value when they wish only to use the dictionary’s default values."
https://heycam.github.io/webidl/#idl-operations

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[sandersdan]

Hmm, not so sure about this one. The current shape comes from a previous iteration where fullRange was not optional, and I don't expect to add new required fields in the future, but it doesn't really make sense to construct a default VideoColorSpace.

We could do something like make primaries required, the concern is that this needlessly complicates cases where apps are translating existing incomplete metadata.

There is some tension here where colorSpace is always nullable/optional in our IDL which is treated the same as a default VideoColorSpace. There was at least some question about making it required (with a default); if we had done that then it would be useful to construct a default VideoColorSpace.

[tidoust]

I see that there is an open discussion to "consider a pattern for dictionary arguments which must have at least one member" in Web IDL, see whatwg/webidl#903

Without that pattern, the constraint needs to be specified in prose, e.g. by throwing a TypeError in the constructor if none of the members were set as done in getUserMedia().

[sandersdan]

I don't think that quite fits our case. After pondering for a while, I think we should just merge this (and also reconsider the question of nullability vs defaults).