The offscreen container is built inside buildGlMap's closure, where the
let lost its narrowing; a const of its own keeps it an HTMLDivElement.
The stage tests hand the stage a t that returns the key, so the toast
reads map.webgl2.terrain there. One floating promise fewer lowers the
eslint baseline to 164.
MapLibre 6 and Mapbox GL 3 both throw out of their Map constructor without
WebGL2. Every place that builds a GL map now asks one helper first,
components/Map/glSupport.ts, and a browser without WebGL2 gets the Leaflet
map with the user's tiles instead of a map that fails to start:
- the trip map (MapViewAuto) and the journey maps (JourneyMapAuto) pick
their renderer through useGlRenderer, which folds in the Mapbox token
rule they each had;
- the settings preview, desktop and phone, shows the Leaflet preview
through useMapSettingsForm and says why under it;
- the tour planner keeps the 2D map when 3D is asked for and says that
3D needs WebGL2;
- the PDF route map and the Leaflet vector basemap already fell back and
now report a GPU failure too.
Behind the probe, buildGlMap wraps each constructor (MapViewGL,
JourneyMapGL, the settings preview, the terrain map, the PDF map). A GPU
that claims WebGL2 and still refuses the context is reported through
utils/webgl, which turns the answer to no and tells every mounted map,
so they switch to Leaflet without a reload; any other error is still
thrown. Two new strings, map.webgl2.fallback and map.webgl2.terrain, in
all 27 locales.
The PDF export on desktop and phone, the language switch, the holiday
regions and the PDF's map image load a chunk on demand and catch the
failure themselves. After a deploy the old page asks for chunk names the
new build no longer has, so they showed their own error on every retry
(or, for the language, silently stayed in the old one) instead of
reloading onto the new build the way an uncaught chunk error does.
importChunk reloads once for a missing chunk and still hands the caller
its error.
Maurice