..

frontend/src/lib/crime-severity-filter.ts

@@ -12,7 +12,7 @@ import {
 
 // "Serious crime" and "Minor crime" are aggregate severity rollups (they overlap
 // the 14 detailed categories, so they must stay OUT of the "Specific crimes"
-// dropdown). Each is a single feature with a 7-year/2-year window toggle — the
+// dropdown). Each is a single feature with a 7-year/2-year window toggle, the
 // same folding the specific-crimes card has, but with no variant dropdown (one
 // variant). Modeled on the multi-filter-name POI pattern: one lib, two filter
 // names, distinguished by their key prefix / bare crime type.

frontend/src/lib/external-search.ts

@@ -152,7 +152,7 @@ export function buildPropertySearchUrls({
       ? Math.max(0, habitableRoomsFilter[1] - 1)
       : undefined;
 
-  // Rightmove — requires locationIdentifier from typeahead API
+  // Rightmove: requires locationIdentifier from typeahead API
   let rightmove: string | null = null;
   if (rightmoveLocationId) {
     const rmParams = new URLSearchParams();
@@ -190,7 +190,7 @@ export function buildPropertySearchUrls({
     rightmove = `https://www.rightmove.co.uk/property-for-sale/find.html?${rmParams.toString()}`;
   }
 
-  // OnTheMarket — postcode slug in URL path (e.g. "SW1A 1AA" → "sw1a-1aa")
+  // OnTheMarket: postcode slug in URL path (e.g. "SW1A 1AA" → "sw1a-1aa")
   const otmSlug = postcode.toLowerCase().replace(/\s+/g, '-');
   const otmParams = new URLSearchParams();
   otmParams.set('radius', String(nearestRadius(radiusMiles, OTM_RADII)));

frontend/src/lib/format.ts

@@ -80,7 +80,7 @@ export function parseInputValue(
 
 export function formatDuration(d: string): string {
   if (d === 'F' || d === 'L') {
-    // These are server enum values — translate via ts()
+    // These are server enum values: translate via ts()
     // eslint-disable-next-line @typescript-eslint/no-var-requires
     const { ts } = require('../i18n/server') as { ts: (v: string) => string };
     if (d === 'F') return ts('Freehold');

frontend/src/lib/listings.test.ts

@@ -0,0 +1,52 @@
+import { describe, expect, it } from 'vitest';
+
+import type { ActualListing } from '../types';
+import { filterListingsByMode, isNewBuildListing } from './listings';
+
+function listing(listing_url: string): ActualListing {
+  return {
+    lat: 51.5,
+    lon: -0.1,
+    postcode: 'N1 1AA',
+    listing_url,
+    features: [],
+  };
+}
+
+const newBuild = listing('https://www.rightmove.co.uk/properties/1#/?channel=RES_NEW');
+const resale = listing('https://www.rightmove.co.uk/properties/2#/?channel=RES_BUY');
+const otherPortal = listing('https://www.onthemarket.com/details/3/');
+
+describe('isNewBuildListing', () => {
+  it('flags RES_NEW channel URLs as new builds', () => {
+    expect(isNewBuildListing(newBuild)).toBe(true);
+  });
+
+  it('treats RES_BUY (resale) as non-new', () => {
+    expect(isNewBuildListing(resale)).toBe(false);
+  });
+
+  it('treats non-Rightmove portals as non-new', () => {
+    expect(isNewBuildListing(otherPortal)).toBe(false);
+  });
+});
+
+describe('filterListingsByMode', () => {
+  const all = [newBuild, resale, otherPortal];
+
+  it('returns everything for "all"', () => {
+    expect(filterListingsByMode(all, 'all')).toEqual(all);
+  });
+
+  it('returns only new builds for "new"', () => {
+    expect(filterListingsByMode(all, 'new')).toEqual([newBuild]);
+  });
+
+  it('excludes new builds for "non-new"', () => {
+    expect(filterListingsByMode(all, 'non-new')).toEqual([resale, otherPortal]);
+  });
+
+  it('returns nothing for "none"', () => {
+    expect(filterListingsByMode(all, 'none')).toEqual([]);
+  });
+});

frontend/src/lib/listings.ts

@@ -0,0 +1,41 @@
+import type { ActualListing } from '../types';
+
+/**
+ * Which slice of the live for-sale listings to render on the map.
+ *
+ * - `all`: every listing in view
+ * - `new`: new-build listings only
+ * - `non-new`: everything that isn't a new build (resale, OnTheMarket, …)
+ * - `none`: hide listings entirely (also skips the fetch)
+ */
+export type ListingsMode = 'all' | 'new' | 'non-new' | 'none';
+
+export const LISTINGS_MODES: readonly ListingsMode[] = ['all', 'new', 'non-new', 'none'];
+
+export const DEFAULT_LISTINGS_MODE: ListingsMode = 'all';
+
+/**
+ * Rightmove encodes the sales channel in the listing URL: `?channel=RES_NEW` for
+ * new-build developments and `?channel=RES_BUY` for ordinary resale. Anything
+ * without `RES_NEW` (resale, OnTheMarket and other portals) is treated as non-new.
+ */
+export function isNewBuildListing(listing: Pick<ActualListing, 'listing_url'>): boolean {
+  return listing.listing_url.includes('RES_NEW');
+}
+
+/** Apply a {@link ListingsMode} to a list of listings. */
+export function filterListingsByMode(
+  listings: ActualListing[],
+  mode: ListingsMode
+): ActualListing[] {
+  switch (mode) {
+    case 'all':
+      return listings;
+    case 'new':
+      return listings.filter(isNewBuildListing);
+    case 'non-new':
+      return listings.filter((listing) => !isNewBuildListing(listing));
+    case 'none':
+      return [];
+  }
+}

frontend/src/lib/map-utils.ts

@@ -24,7 +24,7 @@ export interface PlacedItem<T> {
  * Greedily keep a spaced-out subset of screen-space items so dense areas don't
  * render a wall of overlapping cards. Walks `candidates` in order, keeping one
  * only when it clears every already-kept item by `minDx`/`minDy`, and stops at
- * `max`. Order-dependent by design — pass candidates in priority order.
+ * `max`. Order-dependent by design: pass candidates in priority order.
  */
 export function selectSpacedItems<T>(
   candidates: PlacedItem<T>[],