Re: [webrtc-stats] Clarify that metrics are undefined when their value is not yet determined or unknown (#736)

> "4.2 Guidelines for implementing stats objects" already says to use undefined if "a feature is not applicable"

It doesn't say that. It says: _"When a feature is not applicable to an instance of an object (for example [audioLevel](https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-audiolevel) on a video stream), **omit** the dictionary member. Do NOT report a count of zero, -1 or "empty string"."_

It says to _"omit"_ the member, which is different from a value of `undefined`. [audioLevel](https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-audiolevel): _"Only [exists](https://infra.spec.whatwg.org/#map-exists) for audio."_

E.g. here `audioLevel` [exists](https://infra.spec.whatwg.org/#map-exists):
```js
{audioLevel: undefined}
```
...and here it is omitted:
```js
{}
```
AFAIK WebIDL bindings coerce the former into the latter on _input_ (e.g. dictionaries as arguments to a method), but not output.

-- 
GitHub Notification of comment by jan-ivar
Please view or discuss this issue at https://github.com/w3c/webrtc-stats/issues/736#issuecomment-1452556494 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Thursday, 2 March 2023 21:15:18 UTC