refactor(core): Add experimental support to have one event contract when there are multiple apps on the page. (#57355)

iteriani · AndrewKushnir · commit e30c60e89fef · 2024-08-13T12:10:35.000-07:00
This may be removed if this turns out not to work out so well... PR Close #57355
diff --git a/packages/core/src/event_dispatch/event_delegation.ts b/packages/core/src/event_dispatch/event_delegation.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {EventContract} from '@angular/core/primitives/event-dispatch';
 import {ENVIRONMENT_INITIALIZER, Injector} from '../di';
 import {inject} from '../di/injector_compatibility';
 import {Provider} from '../di/interface/provider';
@@ -18,10 +19,18 @@ import {
 
 import {IS_GLOBAL_EVENT_DELEGATION_ENABLED} from '../hydration/tokens';
 
+declare global {
+  interface Window {
+    __jsaction_contract: EventContract | undefined;
+  }
+}
+
 /**
  * Returns a set of providers required to setup support for event delegation.
+ * @param multiContract - Experimental support to provide one event contract
+ * when there are multiple binaries on the page.
  */
-export function provideGlobalEventDelegation(): Provider[] {
+export function provideGlobalEventDelegation(multiContract = false): Provider[] {
   return [
     {
       provide: IS_GLOBAL_EVENT_DELEGATION_ENABLED,
@@ -32,7 +41,12 @@ export function provideGlobalEventDelegation(): Provider[] {
       useValue: () => {
         const injector = inject(Injector);
         const eventContractDetails = injector.get(JSACTION_EVENT_CONTRACT);
+        if (multiContract && window.__jsaction_contract) {
+          eventContractDetails.instance = window.__jsaction_contract;
+          return;
+        }
         initGlobalEventDelegation(eventContractDetails, injector);
+        window.__jsaction_contract = eventContractDetails.instance;
       },
       multi: true,
     },
