Allow Null Values in Data Driven Styles

[hjbdev]

Motivation

I'm importing GeoJSON into a mapbox map, I have two data sets, lines and points. My lines require different styling based on criteria in the properties in the GeoJSON.

For line-color, the data driven properties work fine. My issue is that some of my lines need a border/outline on, so to resolve this I'm using a repeatable pattern. However, I only want this to be on certain lines, not all. I thought that maybe adding null as the default would achieve this, however it doesn't. line-pattern overrides line-color, which would be fine if I could null the pattern when I want the color, but I can't.

I'd like to avoid making two sets of GeoJSON just for lines, it'll get quite unwieldy.

Design Alternatives

Allow a null value in data driven styles, which would equivalate to not having a value there at all for that specific map feature.

Mock-Up

To a developer this would look similar to the below:

paint: {
    'line-color': [
        'match', ['get', 'my_property'],
        'outline_please', 'my-outline-style',
        null // this is the default
    ]
}

Implementation

Don't think too much would have to change in order to implement this but I'm not particularly familiar with the source code for Mapbox GL so I could be wrong here.

[asheemmamoowala]

@hjbdev Thanks for opening this request. I am closing this because it is a duplicate of #8331. A work-around has been posted at #8331 (comment) until this functionality is available.