feat(react-native): postMessage broadcast options (#75)

* feat(react-native): postMessage broadcast options

* docs: broadcast

* fix: docs

* feat: default value false

* fix: false

* refactor: early ret

docs/using-a-post-message.md

@@ -171,3 +171,20 @@ const unsubscribe2 = bridge.addEventListener("eventName2", (message) => {
 });
 unsubscribe2(); // Unsubscribe from the event
 ```
+
+
+# Broadcast
+
+Due to React Navigation and other factors, there can be multiple instances of a WebView. Sometimes, you may want to send messages to all WebView instances, while at other times, you may only want to target the last WebView instance (e.g., the top of the React Navigation stack).
+
+To send a message to all WebView instances:
+```ts
+postMessage(..., ..., { broadcast: true });
+```
+
+To send a message only to the last WebView instance:
+```ts
+postMessage(..., ...); // @default false
+// or 
+postMessage(..., ..., { broadcast: false });
+```

packages/react-native/src/createWebView.tsx

@@ -152,17 +152,33 @@ export const createWebView = <
     >(
       eventName: EventName,
       args: Args,
+      options: {
+        /**
+         * If `true`, the message will be broadcasted to all webviews.
+         * @default false
+         */
+        broadcast: boolean;
+      } = {
+        broadcast: false,
+      },
     ) => {
       let _args: any = args;
       if (postMessageSchema) {
         _args = postMessageSchema[eventName].validate(args);
       }
-
-      for (const ref of webviewRefList) {
-        ref?.current?.injectJavaScript(
-          SAFE_NATIVE_EMITTER_EMIT(`postMessage/${String(eventName)}`, _args),
-        );
+      if (options.broadcast) {
+        for (const ref of webviewRefList) {
+          ref?.current?.injectJavaScript(
+            SAFE_NATIVE_EMITTER_EMIT(`postMessage/${String(eventName)}`, _args),
+          );
+        }
+        return;
       }
+
+      const lastRef = webviewRefList[webviewRefList.length - 1];
+      lastRef?.current?.injectJavaScript(
+        SAFE_NATIVE_EMITTER_EMIT(`postMessage/${String(eventName)}`, _args),
+      );
     },
     WebView: forwardRef<BridgeWebView, WebViewProps>((props, ref) => {
       const webviewRef = useRef<WebView>(null);