React Native raw event EventEmitter - intended for app-specific perf listeners and debugging

packages/react-native-renderer/src/ReactNativeEventPluginOrder.js

@@ -8,6 +8,7 @@
  */
 
 const ReactNativeEventPluginOrder = [
+  'ReactNativeEventTelemetryPlugin', // We want telemetry to run before any other work is done.
   'ResponderEventPlugin',
   'ReactNativeBridgeEventPlugin',
 ];

packages/react-native-renderer/src/ReactNativeEventTelemetryPlugin.js

@@ -0,0 +1,19 @@
+import {RawEventTelemetryEventEmitter} from 'react-native/Libraries/ReactPrivate/ReactNativePrivateInterface';
+
+const ReactNativeEventTelemetryPlugin = {
+  extractEvents: function(
+    topLevelType,
+    targetInst,
+    nativeEvent,
+    nativeEventTarget,
+    eventSystemFlags
+  ) {
+    RawEventTelemetryEventEmitter.emitEvent(topLevelType, nativeEvent);
+
+    // We never extract events here, we just forward to the telemetry system.
+    // Thus, returning null here unconditionally is optimal.
+    return null;
+  }
+};
+
+export default ReactNativeEventTelemetryPlugin;

packages/react-native-renderer/src/ReactNativeInjectionShared.js

@@ -22,6 +22,7 @@ import {
   injectEventPluginsByName,
 } from './legacy-events/EventPluginRegistry';
 
+import ReactNativeEventTelemetryPlugin from './ReactNativeEventTelemetryPlugin';
 import ReactNativeBridgeEventPlugin from './ReactNativeBridgeEventPlugin';
 import ReactNativeEventPluginOrder from './ReactNativeEventPluginOrder';
 
@@ -35,6 +36,7 @@ injectEventPluginOrder(ReactNativeEventPluginOrder);
  * them).
  */
 injectEventPluginsByName({
+  ReactNativeEventTelemetryPlugin: ReactNativeEventTelemetryPlugin,
   ResponderEventPlugin: ResponderEventPlugin,
   ReactNativeBridgeEventPlugin: ReactNativeBridgeEventPlugin,
 });

packages/react-native-renderer/src/__mocks__/react-native/Libraries/ReactPrivate/RawEventTelemetryEventEmitter.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+const RawEventTelemetryEventEmitter = {
+  emitEvent: jest.fn(),
+};
+
+module.exports = RawEventTelemetryEventEmitter;

packages/react-native-renderer/src/__mocks__/react-native/Libraries/ReactPrivate/ReactNativePrivateInterface.js

@@ -41,4 +41,7 @@ module.exports = {
   get legacySendAccessibilityEvent() {
     return require('./legacySendAccessibilityEvent');
   },
+  get RawEventTelemetryEventEmitter() {
+    return require('./RawEventTelemetryEventEmitter');
+  },
 };