Clarification on [NoInterfaceObject] for SVGPathSegment and Usage of setPathData()

[lovasoa]

Hi ! I'm a simple web developer, maintainer of the wbo.ophir.dev open source whiteboard, which was recently struck by lovasoa/whitebophir#321

I'm seeking clarification on the design decision to mark SVGPathSegment with [NoInterfaceObject] in the SVG specification: https://svgwg.org/specs/paths/#InterfaceSVGPathSegment

This attribute prevents direct instantiation of SVGPathSegment objects in JavaScript, which complicates the use of methods like setPathData() that expect a sequence of SVGPathSegment objects.

Given that SVGPathSegment isn't directly constructible, how are developers intended to create and pass path segment objects to setPathData()? Is the expectation to use plain JavaScript objects that match the structure of SVGPathSegment ? Then shouldn't we have:

dictionary SVGPathSegmentInit {
  required DOMString type;
  required sequence<float> values;
};

interface mixin SVGPathData {
  sequence<SVGPathSegment> getPathData(optional SVGPathDataSettings settings = {});
  undefined setPathData(sequence<SVGPathSegmentInit> pathData);
};

Thank you for your insights !

[longsonr]

Trying to implement this in https://phabricator.services.mozilla.com/D245342