v0.12.2

Changelog

• Add multi-density (groupby) and stack option support to density 1D marks.
• Add normalize option to to density 1D marks.
• Add density groups example.
• Add queryFieldInfo and jsType utilities to mosaic-core exports. (thanks @kwonoh!)
• Fix stack option support, treat them as constant mark channels.
• Fix menu input to support null value options.
• Fix dynamic column handling.

Full Changelog: v0.12.1...v0.12.2