Cannot get MarkerLayer to work

[MarkR-triad]

<MarkerLayer
	filter={['all', ['==', '$type', 'Point'], ['==', 'prop', value]]}
></MarkerLayer>

1. Am I missing some parameters - for example does it use default styling for markers
2. Does MarkerLayer work for MultiPoint, putting a marker on each coordinate
3. Is there any way of seeing what the result of the filter is.

I'm using Svelte 4 not Svelte 5

[dimfeld]

First, I think you want something like this for the filter:

['all', 
  ['==', 'geometry-type', 'Point'],
  ['==', ['get', 'prop'], value]
]

References for those items in the mapbox docs (which are the same in maplibre)

• geometry-type
• get

To your questions:

1. Yeah, it's using the Marker internally which expects you to provide your own content in the slot. Otherwise you end up with an empty div. We could probably check $$slots.default to see if content is provided, and use DefaultMarker instead if none is provided.
2. I think it doesn't, it will calculate the centroid instead and place a single marker. Sounds like a good idea though.
3. I don't think there's a simple way to do it. Something could probably be hacked together, like an Inspect component that would just log whatever comes out of the query. I haven't tried the below at all but it might work.

<script lang="ts">
  import { mapContext, FillLayer } from 'svelte-maplibre';
  export let filter;
  
  const { map, source } = mapContext();

  $: features = $map?.querySourceFeatures($source, { filter });
  $: console.log(features);
</script>

<!-- Set up an invisible layer so that querySourceFeatures has something to search through. -->
<FillLayer paint={{ 'fill-opacity': 0 }} beforeLayerType="symbol" />

Hope this helps!

[MarkR-triad]

Thanks very much for this - I really appreciate it.

One follow up question - I seem to be having some problem with 'data-driven' attribute values. Are these fully functional in the svelte4 and svelte5 branches?

e.g.

'line-color': ['match', ['get', 'someProperty], '21', '#0000FF', '#FF0000'],

// should be blue if someProperty is 21, red if not

[dimfeld]

Hmm it should work fine, those types of things are just passed straight into maplibre so I wouldn’t expect to have any issues from the library itself.