Fix module initialization

Author: lostintangent

CodePush.js

@@ -27,6 +27,7 @@ async function checkForUpdate(deploymentKey = null) {
    * deployments (e.g. an early access deployment for insiders).
    */
   const config = deploymentKey ? { ...nativeConfig, ...{ deploymentKey } } : nativeConfig;
+  
   const sdk = getPromisifiedSdk(requestFetchAdapter, config);
 
   // Use dynamically overridden getCurrentPackage() during tests.
@@ -368,42 +369,52 @@ async function syncInternal(options = {}, syncStatusChangeCallback, downloadProg
   } 
 };
 
-const CodePush = {
-  AcquisitionSdk: Sdk,
-  checkForUpdate,
-  getConfiguration,
-  getCurrentPackage,
-  log,
-  notifyApplicationReady,
-  restartApp,
-  setUpTestDependencies,
-  sync,
-  InstallMode: {
-    IMMEDIATE: NativeCodePush.codePushInstallModeImmediate, // Restart the app immediately
-    ON_NEXT_RESTART: NativeCodePush.codePushInstallModeOnNextRestart, // Don't artificially restart the app. Allow the update to be "picked up" on the next app restart
-    ON_NEXT_RESUME: NativeCodePush.codePushInstallModeOnNextResume // Restart the app the next time it is resumed from the background
-  },
-  SyncStatus: {
-    CHECKING_FOR_UPDATE: 0,
-    AWAITING_USER_ACTION: 1,
-    DOWNLOADING_PACKAGE: 2,
-    INSTALLING_UPDATE: 3,
-    UP_TO_DATE: 4, // The running app is up-to-date
-    UPDATE_IGNORED: 5, // The app had an optional update and the end-user chose to ignore it
-    UPDATE_INSTALLED: 6, // The app had an optional/mandatory update that was successfully downloaded and is about to be installed.
-    SYNC_IN_PROGRESS: 7, // There is an ongoing "sync" operation in progress.
-    UNKNOWN_ERROR: -1
-  },
-  DEFAULT_UPDATE_DIALOG: {
-    appendReleaseDescription: false,
-    descriptionPrefix: " Description: ",
-    mandatoryContinueButtonLabel: "Continue",
-    mandatoryUpdateMessage: "An update is available that must be installed.",
-    optionalIgnoreButtonLabel: "Ignore",
-    optionalInstallButtonLabel: "Install",
-    optionalUpdateMessage: "An update is available. Would you like to install it?",
-    title: "Update available"
-  }
-};
+let CodePush;
+
+// If the "NativeCodePush" variable isn't defined, then 
+// the app didn't properly install the native module,
+// and therefore, it doesn't make sense initializing 
+// the the JS interface when it wouldn't work anyways.
+if (NativeCodePush) {
+    CodePush = {
+        AcquisitionSdk: Sdk,
+        checkForUpdate,
+        getConfiguration,
+        getCurrentPackage,
+        log,
+        notifyApplicationReady,
+        restartApp,
+        setUpTestDependencies,
+        sync,
+        InstallMode: {
+            IMMEDIATE: NativeCodePush.codePushInstallModeImmediate, // Restart the app immediately
+            ON_NEXT_RESTART: NativeCodePush.codePushInstallModeOnNextRestart, // Don't artificially restart the app. Allow the update to be "picked up" on the next app restart
+            ON_NEXT_RESUME: NativeCodePush.codePushInstallModeOnNextResume // Restart the app the next time it is resumed from the background
+        },
+        SyncStatus: {
+            CHECKING_FOR_UPDATE: 0,
+            AWAITING_USER_ACTION: 1,
+            DOWNLOADING_PACKAGE: 2,
+            INSTALLING_UPDATE: 3,
+            UP_TO_DATE: 4, // The running app is up-to-date
+            UPDATE_IGNORED: 5, // The app had an optional update and the end-user chose to ignore it
+            UPDATE_INSTALLED: 6, // The app had an optional/mandatory update that was successfully downloaded and is about to be installed.
+            SYNC_IN_PROGRESS: 7, // There is an ongoing "sync" operation in progress.
+            UNKNOWN_ERROR: -1
+        },
+        DEFAULT_UPDATE_DIALOG: {
+            appendReleaseDescription: false,
+            descriptionPrefix: " Description: ",
+            mandatoryContinueButtonLabel: "Continue",
+            mandatoryUpdateMessage: "An update is available that must be installed.",
+            optionalIgnoreButtonLabel: "Ignore",
+            optionalInstallButtonLabel: "Install",
+            optionalUpdateMessage: "An update is available. Would you like to install it?",
+            title: "Update available"
+        }
+    }
+} else {
+    log("The CodePush module doesn't appear to be properly installed. Please double-check that everything is setup correctly.");
+}
 
 module.exports = CodePush;