feat: abort if google.maps.version defined (#81)

Author: jpoehnelt

src/index.test.ts

@@ -155,3 +155,12 @@ test("setScript adds a nonce", () => {
   const script = document.head.childNodes[0] as HTMLScriptElement;
   expect(script.nonce).toBe(nonce);
 });
+
+test("loader should resolve immediately when google.maps defined", async () => {
+  const loader = new Loader({ apiKey: "foo" });
+  window.google = { maps: { version: "3.*.*" } as any };
+  console.warn = jest.fn();
+  await expect(loader.loadPromise()).resolves.toBeUndefined();
+  delete window.google;
+  expect(console.warn).toHaveBeenCalledTimes(1);
+});

src/index.ts

@@ -398,6 +398,14 @@ export class Loader {
   }
 
   private execute(): void {
+    if (window.google && window.google.maps && window.google.maps.version) {
+      console.warn(
+        "Aborted attempt to load Google Maps JS with @googlemaps/js-api-loader." +
+          "This may result in undesirable behavior as script parameters may not match."
+      );
+      this.callback();
+    }
+
     if (this.done) {
       this.callback();
     } else {