Notable Additions

• Preliminary support for ARIA accessibility attributes in SVG output. Mark and guide definitions now include automatically-generated roles and labels, which can be customized using description and aria properties. Individual mark items do not include ARIA attributes by default (which helps prevent bloat of both the scenegraph and output SVG), but these can be added using description and aria encoding channels.
• Improve generated HTML form elements for signal bindings. Deployments that use custom CSS for styling bound elements may wish to make minor adjustments.
• dayofyear time unit support for the timeunit transform.
• dayofyear, week, utcdayofyear, and utcweek expression functions.
• Axis domainCap, gridCap, and tickCap properties.

Changelog

Changes from v5.10.1:

monorepo

• Add ARIA attribute generation documentation.
• Update eslint setup, consolidate configuration.
• Update dev dependencies.

vega

• Add calendar test specification.
• Add overview-detail-bins test spec to test suite.
• Update crossfilter test scenes to include description property output.

vega-encode

• Move internal tick, label utilities to vega-scale.
• Fix valid tick check calculation. (#2531)

vega-functions

• Add dayofyear, week, utcdayofyear, utcweek expression functions.

vega-geo

• Fix density utility size input checking bug.

vega-parser

• Add ARIA attribute generation for marks and guides via aria and description properties.
• Add backing scale names to axis, legend datum objects.
• Add zindex support for guide config.
• Add axis domainCap, gridCap, and tickCap properties. (Thanks @kanitw!)

vega-scale

• Add tick, label guide utilities from vega-encode.
• Add domainCaption utility.
• Fix overflow with large domain and small tickMinStep (#2550, thanks @rwoollen!)

vega-scenegraph

• Add ARIA attribute generation to SVG renderers:
  • Parent <g> tags for mark items include automatic role and aria-roleDescription attributes.
  • Parent <g> tags for axes and legends include automatic aria-label captions.
  • Attribute generation for mark and guide definitions can be customized using the aria and description properties. If aria is false, the content is hidden from the accessibility tree by setting aria-hidden SVG attribute. The description property determines the aria-label SVG attribute.
  • Individual mark items do not include ARIA attributes by default, but these can be added using the encoding channels aria and description. If a description is provided and aria !== false, then Vega will generate accompanying role and aria-roledescription attributes for a mark item.
• Provide experimental ariaRole and ariaRoleDescription encoding channels for individual marks, which override the default role and aria-roledescription attributes generated by Vega. However, note that these are experimental features and so may change at a later date.

vega-schema

• Add ARIA accessibility properties to mark, guide, and encode schemas.
• Add axis domainCap, gridCap, and tickCap properties.

vega-time

• Add dayofyear time unit support and corresponding tests.
• Add dayofyear, week, utcdayofyear, utcweek utility functions.
• Add export for TIME_UNITS array of valid time unit strings.

vega-transforms

• Update TimeUnit transform parameter schema to enforce valid time unit strings.

vega-typings

• Add ARIA accessibility properties to mark, guide, and encode typings.
• Add dayofyear option to TimeUnit transform typings.
• Add zindex support for guide config.
• Add axis domainCap, gridCap, and tickCap properties.

vega-view

• Improved semantic HTML for generated signal bindings to form input elements.