Style-spec slots

[davidemerritt]

I was wondering if any discussion had occurred about supporting slots https://docs.mapbox.com/style-spec/reference/slots/.

This would be a really useful tool to help us with layer ordering as we currently have to render all layers (lets say 1-10) - possibly with 0 data - because they are toggleable by the user, to maintain the correct z-index.

[HarelM]

Not that I'm aware of, generally speaking, we can't copy from mapbox so I wouldn't know how to reconcile this...

[davidemerritt]

Is there a way to create a feature request, or is this the best forum for that.

Our use case is explicitly ordered layers that the end user can toggle on/off.

With the current beforeId attribute, each layer wouldneed to understand the other layers (which is tough from a soft architecture perspective). Without using slots or an index approach we have to maintain all of the layers and use {layout: {visibility: 'none'}} to hide the ones that have been toggled off, which seems a bit of an awkward solution, but it does work.

[wipfli]

If your main use case is to toggle the visibility of multiple layers, we might also just think about introducing global variables that can be used by multiple layers...

[boeckMt]

@davidemerritt we have implemented something that might help you, but it is a bit customized for our use case...

We have some generic layer objects that serve as pointers to the layers of maplibre (based on their IDs). If you change the order of them, you can detect the change and move the layers accordingly.

• getLayerChangeOrder
• changeOrderOfLayer
• setVisibility

For Slots we have a similar concept like bottom, middle and top Filtertypes , but it is based on our generic layer objects, which only serve as containers for different LayerSpecification's, so not the layers inside the LayerSpecification