Support delimited fields

[gmaclennan]

ODK Collect returns data from multi-select fields as space-delimited fields, e.g.

{impacts: 'deforestation contamination loss_of_biodiversity'}

This is a little tricky to use heuristics to recognize, so short-term we will probably need to manually define which fields are space-delimited.

They are also tricky to filter. We are restricted in this new version by Mapbox's filter language which only does exact matches on fields - for performance reasons I assume.

I think the solution is to flatten these fields into multiple fields e.g.:

{
  'impacts.0': 'deforestation',
  'impacts.1': 'contamination',
  'impacts.2': 'loss_of_biodiversity'
}

Then set the same filter on each of those fields. With datasets when many options are selected in a multi-select this might be a performance issue, but we will have to see. In many datasets there will only be max 3-4 options selected - in our field analysis we can track the max number so we only need ot set that number of filters.

[GoGoCarl]

Ah, this explains some of the odd behaviors I'd been seeing in these fields. Yes, definitely need this! @karissa do you think you could add this to the roadmap?

[gmaclennan]

@GoGoCarl for now if you convert these fields to arrays before passing them to MapFilter it should just work. MapFilter has no way of detecting these manually. The filter issue should work for these too.

[GoGoCarl]

Yep, that did the trick, thanks!