Add a GeoJSON line

Replicates the MapLibre example Add a GeoJSON line. Where the original hand-builds a Feature<LineString> inside addSource, the route: sugar takes just the coordinates.

The complete document

add-a-geojson-line.yaml

# yaml-language-server: $schema=https://docs.maplibre-yaml.org/schema/latest/map.schema.json
# Gallery twin of https://maplibre.org/maplibre-gl-js/docs/examples/add-a-geojson-line/
# The `route:` sugar stands in for the hand-built Feature<LineString>.
type: map
id: add-a-geojson-line
config:
  center: [-122.486052, 37.830348]
  zoom: 14
  mapStyle: "https://demotiles.maplibre.org/style.json"
layers:
  - id: route
    type: line
    source:
      type: geojson
      route:
        name: Lombard Street
        coordinates:
          - [-122.483696, 37.833818]
          - [-122.483482, 37.833174]
          - [-122.483396, 37.8327]
          - [-122.483568, 37.832056]
          - [-122.48404, 37.831141]
          - [-122.48404, 37.830497]
          - [-122.483482, 37.82992]
          - [-122.483568, 37.829548]
          - [-122.48507, 37.829446]
          - [-122.4861, 37.828802]
          - [-122.486958, 37.82931]
          - [-122.487001, 37.830802]
          - [-122.487516, 37.831683]
          - [-122.488031, 37.832158]
          - [-122.488889, 37.832971]
          - [-122.489876, 37.832632]
          - [-122.490434, 37.832937]
          - [-122.49125, 37.832429]
          - [-122.491636, 37.832564]
          - [-122.492237, 37.833378]
          - [-122.493782, 37.833683]
    layout:
      line-join: round
      line-cap: round
    paint:
      line-color: "#888888"
      line-width: 8

What to notice

• route: expands to a Feature<LineString> at parse time — the emitted style.json carries canonical GeoJSON, so nothing downstream knows sugar was involved.
• layout and paint keys are the MapLibre style-spec names, verbatim; no translation table to learn.