v134 · css

Expose CSSFontFeaturesValueRule

We were accidentally missing the [Exposed=Window] on the CSSFontFeaturesValueRule interface, so window.CSSFontFeaturesValueRule is incorrectly undefined even though the API was otherwise exposed.

concepts

  1. CSSFontFeaturesValueRule

    @font-feature-values rules expose a proper CSSFontFeaturesValueRule object. Tooling no longer has to parse the text body.

  2. Style-inspector tree

    The motivating consumer: tooling that walks CSSOM looking for font-feature rules. Side-by-side CSSOM walk vs. the regex-on-cssText fallback that tools had to ship pre-134.

  3. Font Glyph Lab

    Author a live @font-feature-values block, apply aliases to a sample, then read the rule back via the newly-exposed CSSFontFeaturesValueRule.

  4. Font Feature Catalog

    Walk the CSSOM to find every @font-feature-values rule, read fontFamily, blockType, and aliases via CSSFontFeaturesValueRule, and toggle aliases to see live font rendering changes.

why it shipped

We were accidentally missing the [Exposed=Window] on the CSSFontFeaturesValueRule interface, so window.CSSFontFeaturesValueRule is incorrectly undefined even though the API was otherwise exposed.

references