vibes

frontend/src/lib/url-state.ts

@@ -50,6 +50,7 @@ import {
 } from './poi-distance-filter';
 import { dedupeTravelTimeEntries } from './travel-params';
 import { isOverlayId, type OverlayId } from './overlays';
+import { isBasemapId, type BasemapId } from './basemaps';
 
 const POI_NONE_PARAM = '__none';
 
@@ -58,6 +59,7 @@ export interface UrlState {
   filters: FeatureFilters;
   poiCategories: Set<string>;
   overlays: Set<OverlayId>;
+  basemap: BasemapId;
   tab: 'properties' | 'area';
   travelTime?: TravelTimeInitial;
   postcode?: string;
@@ -213,6 +215,7 @@ export function parseUrlState(): UrlState {
     filters: parseFilters(params),
     poiCategories: new Set(),
     overlays: new Set(),
+    basemap: 'standard',
     tab: 'area',
   };
 
@@ -253,6 +256,11 @@ export function parseUrlState(): UrlState {
     result.overlays = new Set(overlayParams.filter(isOverlayId));
   }
 
+  const basemap = params.get('basemap');
+  if (basemap && isBasemapId(basemap)) {
+    result.basemap = basemap;
+  }
+
   // Tab: full name
   const tab = params.get('tab');
   if (tab === 'properties' || tab === 'area') {
@@ -320,7 +328,8 @@ export function stateToParams(
   rightPaneTab: 'properties' | 'area',
   travelTimeEntries?: TravelTimeEntry[],
   share?: string,
-  selectedOverlays?: Set<OverlayId>
+  selectedOverlays?: Set<OverlayId>,
+  basemap?: BasemapId
 ): URLSearchParams {
   const params = new URLSearchParams();
 
@@ -409,6 +418,10 @@ export function stateToParams(
     }
   }
 
+  if (basemap && basemap !== 'standard') {
+    params.set('basemap', basemap);
+  }
+
   // Travel time: repeated `tt` params
   if (travelTimeEntries) {
     for (const entry of dedupeTravelTimeEntries(travelTimeEntries)) {