v2.1.1

Vega:

• Add CountPattern transform.
• Facet transform no longer requires a "groupby" directive.
• Add interactivity to Force transform.
• Add Lookup transform.
• Add Wordcloud transform.
• Add Voronoi transform.
• Deprecate Zip transform. (Use Lookup instead.)
• Add locale formatting support (via datalib 1.4.3)
• Add "open" expression function for hyperlinking.
• Refine schema and test cases.
• Miscellaneous bug fixes.

Vega Editor:

• Add airports, force_drag and wordcloud examples.
• Modify choropleth and force examples to use lookup transform.

2.0

• Declarative interaction design using Signals and Predicates.
• Support for streaming data sets.
• A "reactive geometry" which allows generated mark instances to be used as the backing data for downstream marks.
• Overhauled scenegraph construction, rendering, and event handling with the vega-scenegraph module:
  • Parity between Canvas and SVG modes.
  • Improved performance of SVG renderer.
  • Support for incremental re-rendering.
• Improved editor (now found in the vega-editor repository) with syntax highlighting, code folding, and error icons for JSON parse errors.
• JSON schema to validate Vega specifications against.
• More expressive aggregate and facet data transforms.
• Major improvements to code quality via jshint and extensive unit tests.