Custom Facet

[RFSH]

In some deployments we want to have more complicated facet filters that are not understandable by simple custom filters, and also the UI doesn't know how to handle.

For this use-case, we decided to introduce a new custom-facet blob which will have the same syntax as facet but won't be merged with facet in the client. Then recordset still can function. The same way that we are showing the whole custom-filter in a chicklet, we're going to show this custom-facet in a separate chicklet. We should also be able to change the value that is displayed to the user in the chicklet.

more information about the minimum combination of and/or that should be supported is missing

@hongsudt can you please update the description with more information about what type of filters we want to support?

[RFSH]

It seems like for now we just want "and" of "and"s which can be supported with the current syntax of facet. So all we should do is adding the support for *::cfacets::blob to ermrestjs. The blob will be encoded the same way as facet and the object will have the following format:

{
  "displayname": "a markdown displayname",
  "ermrest_path": "ermrest path",
  "facets": {
    "and": [
      {"source": "F1", "choices": ["1"]},
      {"source": "F1", "choices": ["2"]}, ...
    ]
  }
}

Other improvements that can be done later:

• One problem that using the current syntax has is performance. For each of the source facets we are going to traverse the path and then do the filter. Now in this case, these sources will be identical. We could instead traverse the path once and then "and" the filters. This could be added as a different mode in the current syntax, to treat the values in the choices array as conjunction instead of disjunction.
• Investigate how we can do "or" of "and"s. I'm not sure how this can be achieved in ermrest.