Re: [csswg-drafts] [web-animations-2] Progress APIs (#8799)

Overall it seems reasonable to me. I think defining it in terms of `startTime` and `endTime` is a nice way of keeping it at arms length from effect timing.

> Note that endTime is infinite when either iterations or duration is infinite. In these cases currentProgress should probably be null or undefined?

Mathematically, should it be zero? Not sure if that would be the most useful result, however.

> Open question - should it be read only or should we allow setting the progress which would be equivalent to setting currentTime to currentProgress * endTime?

I'd suggest making it readonly. As you pointed out, there are some cases where this value would be `null` / `undefined` / `0` or somesuch, and in those cases if set made it writeable I guess the setter would throw?

We already have enough ways of changing the animation position (setting `currentTime`, setting `startTime`, calling the various playback methods etc.) and it's easy enough to make a read-only attribute writeable later if compelling use cases present themselves.

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Received on Saturday, 6 May 2023 01:22:42 UTC