fix: move warning and return if already defined

src/index.test.ts

@@ -329,6 +329,16 @@ test("loader should resolve immediately when google.maps defined", async () => {
   expect(console.warn).toHaveBeenCalledTimes(1);
 });
 
+test("loader should not warn if done and google.maps is defined", async () => {
+  const loader = new Loader({ apiKey: "foo" });
+  loader["done"] = true;
+  window.google = { maps: { version: "3.*.*" } as any };
+  console.warn = jest.fn();
+  await expect(loader.loadPromise()).resolves.toBeUndefined();
+  delete window.google;
+  expect(console.warn).toHaveBeenCalledTimes(0);
+});
+
 test("deleteScript removes script tag from head", () => {
   const loader = new Loader({ apiKey: "foo" });
   loader["setScript"]();

src/index.ts

@@ -482,18 +482,21 @@ export class Loader {
   }
 
   private execute(): void {
-    if (window.google && window.google.maps && window.google.maps.version) {
-      console.warn(
-        "Google Maps already loaded outside @googlemaps/js-api-loader." +
-          "This may result in undesirable behavior as options and script parameters may not match."
-      );
-      this.callback();
-    }
-
     this.resetIfRetryingFailed();
+
     if (this.done) {
       this.callback();
     } else {
+      // short circuit and warn if google.maps is already loaded
+      if (window.google && window.google.maps && window.google.maps.version) {
+        console.warn(
+          "Google Maps already loaded outside @googlemaps/js-api-loader." +
+            "This may result in undesirable behavior as options and script parameters may not match."
+        );
+        this.callback();
+        return;
+      }
+
       if (this.loading) {
         // do nothing but wait
       } else {