[css-houdini-drafts] [css-typed-om] `CSSTransformComponent` attributes are under- or incorrectly specced (#1153)

AtkinsSJ has just created a new issue for https://github.com/w3c/css-houdini-drafts:

== [css-typed-om] `CSSTransformComponent` attributes are under- or incorrectly specced ==
Came across a couple of issues while implementing `CSSTranslate`, but they apply to others:

Many of these attributes' behaviour (for example the `x`/`y`/`z` attributes of `CSSTranslate`), are not specced at all.

Second, the spec for the `x`/`y`/`z` attributes on `CSSRotate` and `CSSScale` say:

> The x, y, and z attributes must, on setting to a new value val, [rectify a numberish value](https://drafts.css-houdini.org/css-typed-om-1/#rectify-a-numberish-value) from val and set the corresponding internal slot to the result of that.

Rectifying a numberish value doesn't seem to do anything here. The IDL attribute is already a `CSSNumericValue`, not a `CSSNumberish`, so rectifying it is a no-op.

Also, the WPT tests (eg https://wpt.live/css/css-typed-om/stylevalue-subclasses/cssTranslate.tentative.html) expect these to throw a `TypeError` if they are set to a value that does not match the expected numeric type, similar to the errors thrown in the constructor. This makes sense, but isn't mentioned in the spec.

Please view or discuss this issue at https://github.com/w3c/css-houdini-drafts/issues/1153 using your GitHub account


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Received on Friday, 12 September 2025 15:59:10 UTC