Indicate to user which facets have results

[acouch]

Summary

Facets in search pages with faceted search results are typically limited to the facets with available results. Users are able to drill-down and reduce the available facets and results as they select facets. Some examples include ElasticSearch's test page and https://catalog.data.gov/dataset and the current Grants.gov search engine.

This is a feature of ElasticSearch's API. Enabling this would require us to update the API and the way that the facets are rendered on the search page. This is a feature that would need to be broken down into tasks.

The UX should be determined based on user feedback. There remains an open questions as to whether facets with zero results should be hidden. It is often an anti-pattern to remove choice from the user, especially when they can arrive at a UI with options already hidden and be unaware of available options. We might somehow indicate or disable options that have no results instead of hiding them altogether.

Acceptance criteria

• [ ] Tasks for limited results to facets with available data created

[rylew1]

Should we wait for usability testing feedback before even further refining these? Same for #1831