Vega is a visualization grammar, a declarative format for creating, saving, and sharing interactive visualization designs. With Vega you can describe data visualizations in a JSON format, and generate interactive views using either HTML5 Canvas or SVG.

For documentation, tutorials, and examples, see the Vega website. For a description of changes between Vega 2 and Vega 3, please refer to the Vega 3 Porting Guide. Additional API documentation for Vega 3 can be found in the associated modules listed below.

For a basic setup allowing you to build Vega and run examples, clone https://github.com/vega/vega and run npm install.

Once installation is complete, use npm run test to run tests and npm run build to build output files.

This repo (vega) includes web-based demos within the test folder. To run these, launch a local webserver in the top-level directory for the repo (e.g., python -m SimpleHTTPServer 8000 for Python 2, python -m http.server 8000 for Python 3) and then point your browser to the right place (e.g., http://localhost:8000/test/).

For a more advanced development setup in which you will be working on multiple modules simultaneously, first clone the relevant Vega 3 modules. Here is a list of all Vega 3 repositories:

• https://github.com/vega/vega
• https://github.com/vega/vega-crossfilter
• https://github.com/vega/vega-dataflow
• https://github.com/vega/vega-encode
• https://github.com/vega/vega-event-selector
• https://github.com/vega/vega-expression
• https://github.com/vega/vega-force
• https://github.com/vega/vega-geo
• https://github.com/vega/vega-hierarchy
• https://github.com/vega/vega-loader
• https://github.com/vega/vega-parser
• https://github.com/vega/vega-projection
• https://github.com/vega/vega-runtime
• https://github.com/vega/vega-scale
• https://github.com/vega/vega-scenegraph
• https://github.com/vega/vega-statistics
• https://github.com/vega/vega-transforms
• https://github.com/vega/vega-util
• https://github.com/vega/vega-view
• https://github.com/vega/vega-view-transforms
• https://github.com/vega/vega-voronoi
• https://github.com/vega/vega-wordcloud

Though not strictly required, we recommend using npm link to connect each local copy of a repo with its 'vega-' dependencies. That way, any edits you make in one repo will be immediately reflected within dependent repos, accelerating testing.

For example, to link vega-dataflow for use by other repos, do the following:

# register a link to vega-dataflow
cd vega-dataflow; npm link
# update vega-runtime to use the linked version of vega-dataflow
cd ../vega-runtime; npm link vega-dataflow
# update vega to use the linked version of vega-dataflow
cd ../vega; npm link vega-dataflow

Once links have been setup, you can use npm install as usual to gather all remaining dependencies.