[MPT-13] Search: Filtering by certain combinations removes facets from the screen

[luodan01]

Certain facets are sometimes undisplayed as the user checks other facets, eventually reaching a point where they are unable to return to viewing the original list of mentors by unchecking the facets. Steps to replicate: starting from the full list of mentors, do the following in order

1. check this

2. check this

Then this is the screen as seen:

3. uncheck 'BASF Southeast Asia'

'University of the Philippines' is no longer shown but still reflected under query parameters. It is not obvious how the user can return to the full list of mentors from this state. Issue seems somewhat resolved if disjunctiveFacets is removed from the code but not sure why this is the case

_MPT-13

[IvanFengJK]

I have looked at the disjunctiveFacets documentation here: https://docs.elastic.co/search-ui/api/react/components/facet

Specifically the line 85 in App.tsx disjunctiveFacets: ["organisation", "school", "course_of_study"],

"Disjunctive" facets are facets that do not change when a selection is made. Meaning, all available options will remain as selectable options even after a selection is made.

This means that once we have selected "University of Philippines", the other university options will still be available and thus result in too long a list of university names and cause the option for "University of Philippines" to disappear.

If we were to remove "school" from the array, then you will not be able to select any other schools unless you unselect "University of Philippines" thus leaving the "University of Philippines" not to disappear from the filters. However, this means that you will no longer be able to filter by OR operation but filter only by the MATCH operation.

I think a cleaner solution would be to look at how is the list of the facet ordered and see if we can have the checked boxes always be placed at the top of the list of filters. I am not sure if this is possible. Will do a bit more research in this direction

[IvanFengJK]

This problem is also stated here: elastic/app-search-javascript#24

The proposed solution of reordering the selected facet is currently not available using the API so may need to have a customized solution.

[wei2912]

Issue to be deferred till after 2023 Wave, due to high effort required.