Vega 2 migration basics

[kanitw]

• [x] use the new name mark property in groups

  Field

• [x] remove .data direct access — use fieldRef instead
• [x] remove .data from field
• [x] index => _id in field
• [x] replaced mark’s group property with field.group #593

  Scale

• [x] use scale’s sort for sorting (Done in #612)

  Transform

• [x] stats => aggregate (Done in #604)
• Facet
  • [x] keys => groupby (Done in #604)
  • [x] Eliminate keys.0 reference
• [x] Stack #412
• [x] Check if we use any of removed transforms: array, copy, flatten, slice, truncate, unique, window (We did not)
• [x] Table Heatmap
• [ ] Valid test cases against Vega 2 JSON Schema (forked to #613)

[marcprux]

I noticed this issue became unassigned yesterday. I can do some work on it if it would be helpful.

The Vega 2 JSON schema will be useful for validating that the compiled specs are correct.

[kanitw]

@mprudhom Umm it’s actually not truly “unassigned". I didn’t expect people tracking our issues assignment so I just unassigned this so that I can track stuff I want to do in the next 2 weeks on https://github.com/issues/assigned.

I plan to do this in August. Since it might will be a large PR that affects other apps downstream, I prefer to do it myself. But yes, we plan to use vega2 JSON schema to validate output.

If you have some times to help, we actually listed a number of issues in Vega-lite and Polestar as “help-wanted”. So you might want to take a look at some of those and send us PRs.