Skip creation of EventManager if module not loaded

[srascar-bubble]

Description

One Line Summary

Prevent the creation of a NativeEventEmitter with null as argument

Details

Creating EventManager when the module is not loaded will generate the following error

Invariant Violation: `new NativeEventEmitter()` requires a non-null argument.

Motivation

This change will affect most likely expo users.
Since version 4.x of OneSignal, EventManager is always created which leads to the error above
when running the app in Expo go and IOS Simulator.

Manual testing

• Create a simple expo project
• Import OneSignal and call OneSignal.init()
• Launch ExpoGo in an IOS simulator

---

This change is 

[erickpiazza]

when this PR will be merged, some prediction I have the same problem

[srascar-bubble]

diff --git a/node_modules/react-native-onesignal/dist/index.js b/node_modules/react-native-onesignal/dist/index.js
index 0958bde..74573a5 100644
--- a/node_modules/react-native-onesignal/dist/index.js
+++ b/node_modules/react-native-onesignal/dist/index.js
@@ -47,7 +47,12 @@ var NotificationReceivedEvent_1 = __importDefault(require("./events/Notification
 exports.NotificationReceivedEvent = NotificationReceivedEvent_1.default;
 var helpers_1 = require("./helpers");
 var RNOneSignal = react_native_1.NativeModules.OneSignal;
-var eventManager = new EventManager_1.default(RNOneSignal);
+var eventManager;
+
+if ((0, helpers_1.isNativeModuleLoaded)(RNOneSignal)) {
+  eventManager = new EventManager_1.default(RNOneSignal);
+}
+
 var OneSignal = /** @class */ (function () {
     function OneSignal() {
     }
diff --git a/node_modules/react-native-onesignal/src/index.ts b/node_modules/react-native-onesignal/src/index.ts
index 561dc0a..d57a4aa 100644
--- a/node_modules/react-native-onesignal/src/index.ts
+++ b/node_modules/react-native-onesignal/src/index.ts
@@ -30,7 +30,11 @@ import { InAppMessage, InAppMessageAction, InAppMessageLifecycleHandlerObject }
 import { isValidCallback, isNativeModuleLoaded } from './helpers';

 const RNOneSignal = NativeModules.OneSignal;
-const eventManager = new EventManager(RNOneSignal);
+let eventManager: EventManager;
+
+if (isNativeModuleLoaded(RNOneSignal)) {
+  eventManager = new EventManager(RNOneSignal);
+}

 // 0 = None, 1 = Fatal, 2 = Errors, 3 = Warnings, 4 = Info, 5 = Debug, 6 = Verbose
 export type LogLevel = 0 | 1 | 2 | 3 | 4 | 5 | 6;

[srascar-bubble]

@erickpiazza for the time being we apply the above patch

react-native-onesignal+4.4.1.patch

[delki8]

I guess this also fixes #1361. Two years and two approvals later, why hasn't this been merged?