deploy

frontend/src/lib/travel-params.test.ts

@@ -0,0 +1,97 @@
+import { describe, expect, it } from 'vitest';
+
+import type { TravelTimeEntry } from '../hooks/useTravelTime';
+import { buildTravelParam, dedupeTravelTimeEntries } from './travel-params';
+
+const bankMedian: TravelTimeEntry = {
+  mode: 'transit',
+  slug: 'bank-tube-station',
+  label: 'Bank',
+  timeRange: [0, 60],
+  useBest: false,
+};
+
+describe('travel-params', () => {
+  it('deduplicates travel entries by backend key and keeps the tightest range', () => {
+    const entries = dedupeTravelTimeEntries([
+      bankMedian,
+      {
+        mode: 'transit',
+        slug: 'bank-tube-station',
+        label: 'Bank tube station',
+        timeRange: [15, 45],
+        useBest: false,
+      },
+      {
+        mode: 'walking',
+        slug: 'bank-tube-station',
+        label: 'Bank',
+        timeRange: [0, 20],
+        useBest: false,
+      },
+    ]);
+
+    expect(entries).toEqual([
+      {
+        mode: 'transit',
+        slug: 'bank-tube-station',
+        label: 'Bank',
+        timeRange: [15, 45],
+        useBest: false,
+      },
+      {
+        mode: 'walking',
+        slug: 'bank-tube-station',
+        label: 'Bank',
+        timeRange: [0, 20],
+        useBest: false,
+      },
+    ]);
+  });
+
+  it('serializes deduplicated entries before backend requests', () => {
+    expect(
+      buildTravelParam([
+        bankMedian,
+        {
+          mode: 'transit',
+          slug: 'bank-tube-station',
+          label: 'Bank',
+          timeRange: [10, 50],
+          useBest: false,
+        },
+      ])
+    ).toBe('transit:bank-tube-station:10:50');
+  });
+
+  it('keeps duplicate blank entries because they are editable placeholders', () => {
+    const blank: TravelTimeEntry = {
+      mode: 'transit',
+      slug: '',
+      label: '',
+      timeRange: null,
+      useBest: false,
+    };
+
+    expect(dedupeTravelTimeEntries([blank, blank])).toHaveLength(2);
+  });
+
+  it('uses an unbounded range when excluding a deduplicated travel filter', () => {
+    expect(
+      buildTravelParam(
+        [
+          bankMedian,
+          {
+            mode: 'transit',
+            slug: 'bank-tube-station',
+            label: 'Bank',
+            timeRange: [10, 50],
+            useBest: false,
+          },
+        ],
+        'tt_transit_bank-tube-station',
+        true
+      )
+    ).toBe('transit:bank-tube-station:0:1440');
+  });
+});

frontend/src/lib/travel-params.ts

@@ -1,5 +1,44 @@
 import type { TravelTimeEntry } from '../hooks/useTravelTime';
 
+function mergeTimeRanges(
+  current: [number, number] | null,
+  next: [number, number] | null
+): [number, number] | null {
+  if (!current) return next;
+  if (!next) return current;
+  return [Math.max(current[0], next[0]), Math.min(current[1], next[1])];
+}
+
+export function dedupeTravelTimeEntries(entries: TravelTimeEntry[]): TravelTimeEntry[] {
+  const result: TravelTimeEntry[] = [];
+  const indexByKey = new Map<string, number>();
+
+  for (const entry of entries) {
+    if (!entry.slug) {
+      result.push(entry);
+      continue;
+    }
+
+    const key = `${entry.mode}:${entry.slug}`;
+    const existingIndex = indexByKey.get(key);
+    if (existingIndex == null) {
+      indexByKey.set(key, result.length);
+      result.push({ ...entry });
+      continue;
+    }
+
+    const existing = result[existingIndex];
+    result[existingIndex] = {
+      ...existing,
+      label: existing.label || entry.label,
+      timeRange: mergeTimeRanges(existing.timeRange, entry.timeRange),
+      useBest: existing.useBest || entry.useBest,
+    };
+  }
+
+  return result;
+}
+
 export function buildTravelParam(
   entries: TravelTimeEntry[],
   excludeFieldKey?: string,
@@ -7,7 +46,7 @@ export function buildTravelParam(
 ): string {
   const segments: string[] = [];
 
-  for (const entry of entries) {
+  for (const entry of dedupeTravelTimeEntries(entries)) {
     if (!entry.slug) continue;
 
     let segment = `${entry.mode}:${entry.slug}`;

frontend/src/lib/url-state.test.ts

@@ -99,6 +99,45 @@ describe('url-state', () => {
     expect(params.getAll('tt')).toEqual(['bicycle:bank:Bank:5:25']);
   });
 
+  it('deduplicates travel-time URL params with the tightest range', () => {
+    window.history.replaceState(
+      {},
+      '',
+      '/?tt=transit:bank-tube-station:Bank:0:60&tt=transit:bank-tube-station:Bank:10:45'
+    );
+
+    const state = parseUrlState();
+
+    expect(state.travelTime?.entries).toEqual([
+      {
+        mode: 'transit',
+        slug: 'bank-tube-station',
+        label: 'Bank',
+        timeRange: [10, 45],
+        useBest: false,
+      },
+    ]);
+
+    const params = stateToParams(null, {}, [], new Set(), 'area', [
+      {
+        mode: 'transit',
+        slug: 'bank-tube-station',
+        label: 'Bank',
+        useBest: false,
+        timeRange: [0, 60],
+      },
+      {
+        mode: 'transit',
+        slug: 'bank-tube-station',
+        label: 'Bank',
+        useBest: false,
+        timeRange: [10, 45],
+      },
+    ]);
+
+    expect(params.getAll('tt')).toEqual(['transit:bank-tube-station:Bank:10:45']);
+  });
+
   it('round-trips an explicitly empty POI selection', () => {
     const params = stateToParams(null, {}, [], new Set(), 'area');