Produce CommonJS and UMD bundles (#932)

package.json

@@ -15,8 +15,8 @@
     "node": ">=10"
   },
   "scripts": {
-    "build": "microbundle-crl --no-compress --format modern,cjs",
-    "start": "microbundle-crl watch --no-compress --format modern,cjs",
+    "build": "microbundle-crl -f cjs,umd src/index.cjs.js && microbundle-crl -f es,modern src/index.js",
+    "start": "microbundle-crl watch -f cjs,umd",
     "prepare": "run-s build",
     "test": "run-s test:unit test:lint test:build",
     "test:build": "run-s build",

src/index.cjs.js

@@ -0,0 +1,23 @@
+import GoogleMap from './google_map';
+
+import {
+  convertNeSwToNwSe,
+  convertNwSeToNeSw,
+  fitBounds,
+  meters2ScreenPixels,
+  tile2LatLng,
+  latLng2Tile,
+  getTilesIds,
+} from './lib';
+
+Object.assign(GoogleMap, {
+  convertNeSwToNwSe,
+  convertNwSeToNeSw,
+  fitBounds,
+  meters2ScreenPixels,
+  tile2LatLng,
+  latLng2Tile,
+  getTilesIds,
+});
+
+export default GoogleMap;

src/index.js

@@ -1,3 +1,13 @@
 import GoogleMap from './google_map';
 
+export {
+  convertNeSwToNwSe,
+  convertNwSeToNeSw,
+  fitBounds,
+  meters2ScreenPixels,
+  tile2LatLng,
+  latLng2Tile,
+  getTilesIds,
+} from './lib';
+
 export default GoogleMap;