veja

A Clojure library for displaying Vega and Vega Lite visualizations in JupyterLab. Simply attaches the appropriate MIME type to the Vega(Lite) definition, defined as Clojure maps/vectors matching the JSON schema.

NOTE - this may work with Jupyter notebook as well, with the right plugin. We haven't tried it.

Usage

Use dependency [provisdom/veja "0.2.0"]

Run JupyterLab using the lein-jupyter plug-in. Version 0.1.16 and above should have JupyterLab support. JupyterLab currently has native support for Vega 2/Vega Lite 1. Vega 3/Vega Lite 2 will become the default in a near-future release of JupyterLab, but until then if you want Vega 3/Vega Lite 2 support (recommended) install the vega3-extension with:

jupyter labextension install @jupyterlab/vega3-extension

The vega* function handles plotting for the various Vega flavors. It has two required arguments: vega-type and vega-data. vega-data is the Vega plot defined as EDN, following the appropriate JSON schema for vega-type. Valid values of vega-type are:

• :vega2 - Vega version 2
• :vega3 - Vega version 3
• :vega-lite1 - Vega Lite version 1
• :vega-lite2 - Vega LIte version 2

The vega* function also accepts an optional third argument, print-validation-result, which will additionally pretty-print the results of JSON schema validation against your Vega definition.

For convenience, the vega and vega-lite functions are defined as follows:

• (def vega (partial vega* :vega3))
• (def vega-lite (partial vega* :vega-lite2))

These provide easy access to the most recent Vega(Lite) versions, and will be updated correspondingly as new Vega versions are rolled out.

Example

(require '[provisdom.veja.core :as veja])

(def bar {:data {:values [{:a "A" :b 28} {:a "B" :b 55} {:a "C" :b 43}
                          {:a "D" :b 91} {:a "E" :b 81} {:a "F" :b 53}
                          {:a "G" :b 19} {:a "H" :b 87} {:a "I" :b 52}]}
          :mark :bar
          :encoding {:x {:field :a, :type :ordinal}
                     :y {:field :b :type :quantitative}}})
                     
(veja/vega-lite bar)

NOTE

Vega may still produce a plot even if JSON schema validation fails, which is why the print-validation-result simply adds to the output and does not throw an exception. Schema validation output can be very verbose in the case of a failure, so unless there's an obvious problem with the chart output, you'll want to leave print-validation-result as the default of false.

License

Copyright © 2018 Provisdom Corp.

Distributed under the MIT License.