An expression to check if an array contains a given value

[dagjomar]

Example:
A feature has properties:

{ colors: ['red', 'green', 'blue'  }

now, I want to filter the features that has one or more of the colors I want to filter on.

filter: ['any', ['inArray', 'colors', 'green'], ['inArray', 'colors', 'blue'] ]

or

filter: [ '!inArray', 'colors', 'green' ]

It seems like the inverse variant of the membership filter 'in' and '!in'

[stevage]

Yes, I have run into this need as well. The use case was a map of events, where each event had several categories. I would like to do:

{ categories: ['Arts','Money','Sport'] }

and

filter: ['inArray', 'categories','Sport']

The workaround in my case was to split all the categories out:

sportCategory:true, artCategory: true, moneyCategory: true

I think that workaround is probably always possible, although it would get cumbersome for large sets.

[dagjomar]

Yeah, for my use case, it will be an evergrowing large set of IDs. For example:
{ categories: [32,44,53,66,235,434] }

So filtering on boolean values is not an option :/

[kkaefer]

This could be subsumed by #4715

[anandthakker]

#4715 will help with one aspect of this, but actually I think the more challenging issue is that the vector tile specification does not support arrays or objects as feature property values. (See #2434, mapbox/vector-tile-spec#75)

[dagjomar]

Oh, doesn't support arrays or objects, that's a kinky thing to work around :/

Ok, how about a function to match a concated string using regex? :p

So, in my case (#4698 (comment))
Instead of the array
{ categories: [32,44,53,66,235,434] }
it would be:
{ categoriesStr: '|32|44|53|66|235|434|' }

and filter:

filter: ['regex', 'categoriesStr', /\|44\|/, true] //Looking in the string to match the string '\|44\|'

The boolean at the end could be used to easily inverse the filter?

Just throwing out ideas here...

[kkaefer]

GeoJSON properties do support arrays, and we have support for parsing them, so I think accessing them as part of the expression syntax is something we should also incorporate.

[1ec5]

Ok, how about a function to match a concated string using regex? :p

Tracked in #4089.

[anandthakker]

Related: #2434

[stevage]

@anandthakker a feature request, not a bug?

[anandthakker]

Whoops, my mistake - thanks @stevage