Working on map view

packages/backend/src/location.ts

@@ -0,0 +1,41 @@
+import * as iplocation from 'iplocation';
+import { Maybe, Types } from '@dotstats/common';
+
+export interface Location {
+  lat: Types.Latitude;
+  lon: Types.Longitude;
+}
+
+const cache = new Map<string, Location>();
+
+export async function locate(ip: string): Promise<Maybe<Location>> {
+  if (ip === '127.0.0.1') {
+    return Promise.resolve({
+      lat: 52.5166667 as Types.Latitude,
+      lon: 13.4 as Types.Longitude
+    });
+  }
+
+  const cached = cache.get(ip);
+
+  if (cached) {
+    return Promise.resolve(cached);
+  }
+
+  return new Promise<Maybe<Location>>((resolve, _) => {
+    iplocation(ip, (err, result) => {
+      if (err) {
+        console.error(`Couldn't locate ${ip}`);
+
+        return resolve(null);
+      }
+
+      const { lat, lon } = result;
+      const location = { lat, lon } as Location;
+
+      cache.set(ip, location);
+
+      resolve(location);
+    });
+  })
+}