refactor(map): share isValidCoordinate and unwrapLongitudes helpers

The coord-validation and antimeridian-unwrap logic added in the last
pass had been duplicated across map.ts, trail_manager.ts, and
info_map.ts. Move both into map_helpers.ts and import from there so
there is one authoritative implementation.

assets/js/features/trail_manager.ts

@@ -7,6 +7,8 @@ import type {
   PolylineOptions,
 } from "leaflet";
 
+import { isValidCoordinate, unwrapLongitudes } from "../map_helpers";
+
 // Declare Leaflet as a global
 declare const L: typeof import("leaflet");
 
@@ -137,19 +139,7 @@ export class TrailManager {
   ) {
     if (!this.showTrails) return;
 
-    // Validate coordinates before processing
+    if (!isValidCoordinate(lat, lng)) {
-    if (
-      typeof lat !== "number" ||
-      typeof lng !== "number" ||
-      isNaN(lat) ||
-      isNaN(lng) ||
-      !isFinite(lat) ||
-      !isFinite(lng) ||
-      lat < -90 ||
-      lat > 90 ||
-      lng < -180 ||
-      lng > 180
-    ) {
       console.warn("Invalid coordinates provided to addPosition:", {
         markerId,
         lat,
@@ -283,27 +273,6 @@ export class TrailManager {
     return R * c;
   }
 
-  // Unwrap a longitude sequence so polylines drawn across the antimeridian
-  // render as a short hop rather than a line wrapping around the world.
-  // Each point's longitude is shifted by a cumulative multiple of 360 so the
-  // delta between consecutive points is always the short-way difference.
-  private unwrapLongitudes(
-    positions: [number, number][],
-  ): [number, number][] {
-    if (positions.length === 0) return [];
-    const unwrapped: [number, number][] = [[positions[0][0], positions[0][1]]];
-    let offset = 0;
-    for (let i = 1; i < positions.length; i++) {
-      const [lat, lng] = positions[i];
-      const prevRawLng = positions[i - 1][1];
-      const delta = lng - prevRawLng;
-      if (delta > 180) offset -= 360;
-      else if (delta < -180) offset += 360;
-      unwrapped.push([lat, lng + offset]);
-    }
-    return unwrapped;
-  }
-
   // Get the average position of a trail. Returns null for empty arrays so
   // callers can't accidentally treat null island (0, 0) as a real center.
   private getTrailCenter(positions: PositionHistory[]): {
@@ -415,21 +384,7 @@ export class TrailManager {
     if (trailState.positions.length >= 2) {
       // Filter out positions with invalid coordinates and create coordinate pairs
       const validPositions: [number, number][] = trailState.positions
-        .filter((pos) => {
+        .filter((pos) => pos && isValidCoordinate(pos.lat, pos.lng))
-          return (
-            pos &&
-            typeof pos.lat === "number" &&
-            typeof pos.lng === "number" &&
-            !isNaN(pos.lat) &&
-            !isNaN(pos.lng) &&
-            isFinite(pos.lat) &&
-            isFinite(pos.lng) &&
-            pos.lat >= -90 &&
-            pos.lat <= 90 &&
-            pos.lng >= -180 &&
-            pos.lng <= 180
-          );
-        })
         .map((pos) => [pos.lat, pos.lng]);
 
       // Calculate total path distance to determine if station is actually moving
@@ -451,7 +406,7 @@ export class TrailManager {
 
       // Unwrap longitudes so segments that cross the antimeridian are drawn as
       // a short local line rather than a polyline stretched across the world.
-      const unwrappedPositions = this.unwrapLongitudes(validPositions);
+      const unwrappedPositions = unwrapLongitudes(validPositions);
 
       // Break trail into segments at giant jumps (bad data / different igates).
       // Hop distance uses the Haversine calculator which normalizes the lng

assets/js/hooks/info_map.ts

@@ -1,24 +1,13 @@
 // Simple map hook for displaying a single station on the info page
 
+import { isValidCoordinate } from "../map_helpers";
+
 declare const L: typeof import("leaflet");
 
 // ~1.1 m at the equator — enough to ignore float noise but still notice any
 // real position change from the server.
 const POSITION_EPSILON = 0.00001;
 
-function isValidLatLng(lat: number, lng: number): boolean {
-  return (
-    !isNaN(lat) &&
-    !isNaN(lng) &&
-    isFinite(lat) &&
-    isFinite(lng) &&
-    lat >= -90 &&
-    lat <= 90 &&
-    lng >= -180 &&
-    lng <= 180
-  );
-}
-
 interface InfoMapContext {
   el: HTMLElement;
   map: import("leaflet").Map | null;
@@ -46,7 +35,7 @@ export const InfoMap = {
     const symbolHtml = this.el.dataset.symbolHtml || null;
     const callsign = this.el.dataset.callsign || "unknown";
 
-    if (!isValidLatLng(lat, lon)) {
+    if (!isValidCoordinate(lat, lon)) {
       console.warn(
         `InfoMap: Invalid coordinates lat=${lat}, lon=${lon} for ${callsign} during update`,
       );
@@ -117,7 +106,7 @@ function initializeMap(this: InfoMapContext) {
   const callsign = this.el.dataset.callsign || "unknown";
   const symbolHtml = this.el.dataset.symbolHtml || null;
 
-  if (!isValidLatLng(lat, lon)) {
+  if (!isValidCoordinate(lat, lon)) {
     console.warn(
       `InfoMap: Invalid coordinates lat=${lat}, lon=${lon} for ${callsign}`,
     );

assets/js/map.ts

@@ -65,6 +65,8 @@ import {
   safePushEvent,
   getLiveSocket,
   escapeHtml,
+  isValidCoordinate,
+  unwrapLongitudes,
 } from "./map_helpers";
 
 // APRS Map Hook - handles only basic map interaction
@@ -1674,17 +1676,9 @@ let MapAPRSMap = {
 
       // Unwrap longitudes so a trail that crosses the antimeridian draws as a
       // short hop instead of a polyline that spans the whole world.
-      const latlngs: [number, number][] = [
+      const latlngs = unwrapLongitudes(
-        [validPoints[0].lat, validPoints[0].lng],
+        validPoints.map((p) => [p.lat, p.lng] as [number, number]),
-      ];
+      );
-      let offset = 0;
-      for (let i = 1; i < validPoints.length; i++) {
-        const prevRawLng = validPoints[i - 1].lng;
-        const delta = validPoints[i].lng - prevRawLng;
-        if (delta > 180) offset -= 360;
-        else if (delta < -180) offset += 360;
-        latlngs.push([validPoints[i].lat, validPoints[i].lng + offset]);
-      }
 
       // Access Leaflet from window
       const L = (window as any).L;
@@ -2650,19 +2644,6 @@ function extractCoordinate(value: any): number {
   return NaN;
 }
 
-// Helper to validate coordinates
-function isValidCoordinate(lat: number, lng: number): boolean {
-  return (
-    !isNaN(lat) &&
-    !isNaN(lng) &&
-    isFinite(lat) &&
-    isFinite(lng) &&
-    lat >= -90 &&
-    lat <= 90 &&
-    lng >= -180 &&
-    lng <= 180
-  );
-}
 
 // Helper to create divIcon with common defaults
 function createDivIcon(

assets/js/map_helpers.ts

@@ -149,3 +149,46 @@ export function isLiveViewConnected(): boolean {
 export function getLiveSocket(): LiveSocket | null {
   return typeof window !== 'undefined' ? window.liveSocket || null : null;
 }
+
+/**
+ * Validate that a lat/lng pair is a real, in-range, finite coordinate.
+ * Used everywhere we receive coordinates from the server or the DOM, so
+ * NaN / Infinity / out-of-range values never reach Leaflet.
+ */
+export function isValidCoordinate(lat: number, lng: number): boolean {
+  return (
+    typeof lat === "number" &&
+    typeof lng === "number" &&
+    !isNaN(lat) &&
+    !isNaN(lng) &&
+    isFinite(lat) &&
+    isFinite(lng) &&
+    lat >= -90 &&
+    lat <= 90 &&
+    lng >= -180 &&
+    lng <= 180
+  );
+}
+
+/**
+ * Unwrap a sequence of [lat, lng] points so a polyline that crosses the
+ * antimeridian renders as a short hop instead of a line looping around the
+ * world. Each point's lng is shifted by a cumulative multiple of 360 so the
+ * delta between consecutive points is always the short-way difference.
+ */
+export function unwrapLongitudes(
+  positions: [number, number][],
+): [number, number][] {
+  if (positions.length === 0) return [];
+  const unwrapped: [number, number][] = [[positions[0][0], positions[0][1]]];
+  let offset = 0;
+  for (let i = 1; i < positions.length; i++) {
+    const [lat, lng] = positions[i];
+    const prevRawLng = positions[i - 1][1];
+    const delta = lng - prevRawLng;
+    if (delta > 180) offset -= 360;
+    else if (delta < -180) offset += 360;
+    unwrapped.push([lat, lng + offset]);
+  }
+  return unwrapped;
+}