iOS开发，刚接手React-native，遇到的问题，求教！

我是用react-native创建了个新应用，但是用Xcode运行，程序崩溃，以下是日志：
2017-02-13 15:13:28.929 [info][tid:main][RCTBatchedBridge.m:72] Initializing <RCTBatchedBridge: 0x60800018a4f0> (parent: <RCTBridge: 0x6080000ac960>, executor: RCTJSCExecutor)
2017-02-13 15:13:28.931 AwesomeProject[14469:275275] *** Assertion failure in -[RCTBatchedBridge loadSource:onProgress:](), /Users/pbph/AwesomeProject/node_modules/react-native/React/Base/RCTBatchedBridge.m:196
2017-02-13 15:13:28.935 AwesomeProject[14469:275275] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'bundleURL must be non-nil when not implementing loadSourceForBridge'
*** First throw call stack:
(
0   CoreFoundation                      0x0000000107e8d34b __exceptionPreprocess + 171
1   libobjc.A.dylib                     0x0000000106d9b21e objc_exception_throw + 48
2   CoreFoundation                      0x0000000107e91442 +[NSException raise:format:arguments:] + 98
3   Foundation                          0x0000000106967d79 -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 166
4   AwesomeProject                      0x000000010647de95 -[RCTBatchedBridge loadSource:onProgress:] + 997
5   AwesomeProject                      0x000000010647c003 -[RCTBatchedBridge start] + 883
6   AwesomeProject                      0x00000001064b54cc -[RCTBridge setUp] + 684
7   AwesomeProject                      0x00000001064b4753 -[RCTBridge initWithDelegate:bundleURL:moduleProvider:launchOptions:] + 387
8   AwesomeProject                      0x00000001064b4562 -[RCTBridge initWithBundleURL:moduleProvider:launchOptions:] + 146
9   AwesomeProject                      0x0000000106417137 -[RCTRootView initWithBundleURL:moduleName:initialProperties:launchOptions:] + 183
10  AwesomeProject                      0x00000001064006d5 -[AppDelegate application:didFinishLaunchingWithOptions:] + 245
11  UIKit                               0x000000010a3ff0be -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 290
12  UIKit                               0x000000010a400a43 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 4236
13  UIKit                               0x000000010a406de9 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1731
14  UIKit                               0x000000010a403f69 -[UIApplication workspaceDidEndTransaction:] + 188
15  FrontBoardServices                  0x000000010d89c723 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 24
16  FrontBoardServices                  0x000000010d89c59c -[FBSSerialQueue _performNext] + 189
17  FrontBoardServices                  0x000000010d89c925 -[FBSSerialQueue _performNextFromRunLoopSource] + 45
18  CoreFoundation                      0x0000000107e32311 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
19  CoreFoundation                      0x0000000107e1759c __CFRunLoopDoSources0 + 556
20  CoreFoundation                      0x0000000107e16a86 __CFRunLoopRun + 918
21  CoreFoundation                      0x0000000107e16494 CFRunLoopRunSpecific + 420
22  UIKit                               0x000000010a4027e6 -[UIApplication _run] + 434
23  UIKit                               0x000000010a408964 UIApplicationMain + 159
24  AwesomeProject                      0x0000000106400aaf main + 111
25  libdyld.dylib                       0x000000010bddf68d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
不知道哪地方出问题了？求赐教！谢谢