Geojson export of visible layers is missing map / layer default attributes

[hholzgra]

A GeoJSON "visible layers only" download only exports individual geometries attributes, not default attributes from the layer or map level

My test has three layers, the default color on the map set to red, layer 1 having no default color of its own set, layers 2 and 3 having green and magenta set as default colors respectively.

I created two polygons on each layer, one using the default color while the other explicitly set to DarkOrange. See attached screenshot, layers are from left to right, with the top polygon using the default color, the bottom one having the color explicitly set.

When exporting as "full backup" I can render the exported geojson in my own app (my MapOSMatic fork) just fine.

But when doing geojson visible layers export the three top polygons all appear in blue (my default color if nothing is set) instead of read, green and magenta inherited from map or layer defaults, only the bottom polygons all come through as DarkOrange as they have that color explicitly set on the geometries themselves.

The exported files look like this:

Full backup:
umap_backup_test2.json

Geojson all visible layers:
test2.json

[hholzgra]

Checking the two exports for the "color" attribute the full backup (after json reformatting) has:

    "color": "Red",
              "color": "DarkOrange"
        "color": "Lime",
              "color": "DarkOrange"
        "color": "Magenta",
              "color": "DarkOrange"

while the visible layers export only has;

          "color": "DarkOrange"
          "color": "DarkOrange"
          "color": "DarkOrange"

[hholzgra]

Test map is https://umap.openstreetmap.fr/en/map/test2_1043461

[yohanboniface]

Not sure how to fix this without pulling each and every property in each and every feature, which sounds suboptimal.

Maybe, when fixing #174 when can expose layers properties also in some way (only in the geojson export format I'd say).

Would that help @hholzgra ?