Gas Station Feature

frontend/src/features/stations/utils/maps-loader.ts

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+/**
+ * @ai-summary Google Maps JavaScript API loader
+ * Handles dynamic loading and singleton pattern
+ */
+
+import { getGoogleMapsApiKey } from '@/core/config/config.types';
+
+let mapsPromise: Promise<void> | null = null;
+
+/**
+ * Load Google Maps JavaScript API dynamically
+ * Uses singleton pattern - only loads once
+ *
+ * @returns Promise that resolves when Google Maps is loaded
+ */
+export function loadGoogleMaps(): Promise<void> {
+  // Return cached promise if already loading/loaded
+  if (mapsPromise) {
+    return mapsPromise;
+  }
+
+  // Create loading promise
+  mapsPromise = new Promise((resolve, reject) => {
+    // Check if already loaded in window
+    if ((window as any).google?.maps) {
+      resolve();
+      return;
+    }
+
+    // Get API key from runtime config
+    const apiKey = getGoogleMapsApiKey();
+
+    if (!apiKey) {
+      reject(new Error('Google Maps API key is not configured'));
+      return;
+    }
+
+    // Create script tag
+    const script = document.createElement('script');
+    script.src = `https://maps.googleapis.com/maps/api/js?key=${apiKey}&libraries=places`;
+    script.async = true;
+    script.defer = true;
+
+    script.onload = () => {
+      if ((window as any).google?.maps) {
+        resolve();
+      } else {
+        reject(
+          new Error('Google Maps loaded but window.google.maps not available')
+        );
+      }
+    };
+
+    script.onerror = () => {
+      // Reset promise so retry is possible
+      mapsPromise = null;
+      reject(new Error('Failed to load Google Maps script'));
+    };
+
+    // Add to document
+    document.head.appendChild(script);
+  });
+
+  return mapsPromise;
+}
+
+/**
+ * Get Google Maps API (after loading)
+ *
+ * @returns Google Maps object
+ * @throws Error if Google Maps not loaded
+ */
+export function getGoogleMapsApi(): typeof google.maps {
+  if (!(window as any).google?.maps) {
+    throw new Error('Google Maps not loaded. Call loadGoogleMaps() first.');
+  }
+
+  return (window as any).google.maps;
+}
+
+/**
+ * Reset loader (for testing)
+ */
+export function resetMapsLoader(): void {
+  mapsPromise = null;
+}