[svgwg] `getPathSegmentAtLength()`: Define behavior for `NaN` distance (#1128)

viralipurbey has just created a new issue for https://github.com/w3c/svgwg:

== `getPathSegmentAtLength()`: Define behavior for `NaN` distance ==
The spec states that the distance parameter to `getPathSegmentAtLength()` "shall be clamped to [0, total-length]". However, `NaN` cannot be meaningfully clamped to a numeric range.

**Proposed resolution**: Return `null` when distance is `NaN`. This aligns with the graceful-degradation model used elsewhere in SVG (no exceptions for invalid numeric inputs) and is consistent with `unrestricted float` semantics. 

Firefox currently returns null for NaN.

For `±Infinity`, clamping to `[0, total-length]` works as expected (`-Infinity` → first segment, `+Infinity` → last segment). Firefox behaves the same way.

https://svgwg.org/svg2-draft/paths.html#DOMInterfaces

Please view or discuss this issue at https://github.com/w3c/svgwg/issues/1128 using your GitHub account


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Received on Wednesday, 10 June 2026 13:34:27 UTC