started work on multiple app initialization

lib/utils/ModuleBase.js

@@ -0,0 +1,83 @@
+/**
+ * @flow
+ */
+import { NativeModules } from 'react-native';
+import Log from '../utils/log';
+import { nativeWithApp } from './../utils';
+import INTERNALS from './../internals';
+
+// logging instances
+
+const logs = {};
+
+export default class ModuleBase {
+  constructor(firebaseApp, options, moduleName) {
+    this._options = Object.assign({}, options);
+    this._module = moduleName;
+    this._firebaseApp = firebaseApp;
+    this._appName = firebaseApp.name;
+    this._namespace = `${this._appName}:${this._module}`;
+
+    // check if native module exists as all native modules are now optionally part of build
+    const nativeModule = NativeModules[`RNFirebase${moduleName}`];
+
+    if (!nativeModule) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_MODULE(moduleName));
+    }
+
+    // used by the modules that extend ModuleBase to access their native module counterpart
+    this._native = nativeWithApp(this._appName, nativeModule);
+  }
+
+  /**
+   * Returns the FirebaseApp instance for current module
+   * @return {*}
+   */
+  get app() {
+    return this._firebaseApp;
+  }
+
+  get log(): Log {
+    if (logs[this._namespace]) return logs[this._namespace];
+    return logs[this._namespace] = Log.createLogger(
+      `🔥 ${this._namespace.toUpperCase()}`,
+    );
+  }
+
+  /*
+   * Proxy functions to shared event emitter instance
+   * https://github.com/facebook/react-native/blob/master/Libraries/EventEmitter/EventEmitter.js
+   */
+  get sharedEventEmitter() {
+    return INTERNALS.SharedEventEmitter;
+  }
+
+  get addListener() {
+    return INTERNALS.SharedEventEmitter.addListener.bind(INTERNALS.SharedEventEmitter);
+  }
+
+  get on() {
+    return INTERNALS.SharedEventEmitter.addListener.bind(INTERNALS.SharedEventEmitter);
+  }
+
+  get emit() {
+    return INTERNALS.SharedEventEmitter.emit.bind(INTERNALS.SharedEventEmitter);
+  }
+
+  get listeners() {
+    return INTERNALS.SharedEventEmitter.listeners.bind(INTERNALS.SharedEventEmitter);
+  }
+
+  hasListeners(eventType: string): Boolean {
+    const subscriptions = INTERNALS.SharedEventEmitter._subscriber.getSubscriptionsForType(eventType);
+    return subscriptions && subscriptions.length;
+  }
+
+  get removeListener() {
+    return INTERNALS.SharedEventEmitter.removeListener.bind(INTERNALS.SharedEventEmitter);
+  }
+
+  get removeAllListeners() {
+    return INTERNALS.SharedEventEmitter.removeAllListeners.bind(INTERNALS.SharedEventEmitter);
+  }
+}