I have just download the clone of this repo but after I start expo it is giving me an error saying:

Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.

Check the render method of `App`.


This error is located at:
    in App (created by ExpoRoot)
    in ExpoRoot (at renderApplication.js:45)
    in RCTView (at View.js:34)
    in View (at AppContainer.js:106)
    in RCTView (at View.js:34)
    in View (at AppContainer.js:132)
    in AppContainer (at renderApplication.js:39)

For some reason, the code as is doesnt export TabBarIcon.js correctly.
I am a beginner so it is hard for me to debug.

undefined is not an object (evaluating '_expo.Icon.MaterialCommunityIcons')

• navigation/MainTabNavigator.js:23:4 in HomeStack.navigationOptions.tabBarIcon

• node_modules/react-navigation-tabs/lib/module/utils/createTabNavigator.js:1:1832 in _this._renderIcon
• node_modules/react-navigation-tabs/lib/module/views/CrossFadeIcon.js:1:1344 in render
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:13042:21 in finishClassComponent
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:12970:4 in updateClassComponent
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:307:15 in invokeGuardedCallbackImpl
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:531:36 in invokeGuardedCallback
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:20488:8 in beginWork$$1
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:19370:24 in performUnitOfWork
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:19347:39 in workLoopSync
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:18997:22 in renderRoot

• [native code]:null in renderRoot

• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:18709:28 in runRootCallback

• [native code]:null in runRootCallback

• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:5642:32 in runWithPriority$argument_1
• node_modules/scheduler/cjs/scheduler.development.js:643:23 in unstable_runWithPriority
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:5638:22 in flushSyncCallbackQueueImpl
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:5627:28 in flushSyncCallbackQueue
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:18556:30 in scheduleUpdateOnFiber
• node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:7799:17 in classComponentUpdater.enqueueSetState
• node_modules/react/cjs/react.development.js:325:31 in Component.prototype.setState

• App.js:52:2 in App

• node_modules/expo/build/launch/AppLoading.js:30:31 in _startLoadingAppResourcesAsync
• node_modules/regenerator-runtime/runtime.js:45:44 in tryCatch
• node_modules/regenerator-runtime/runtime.js:271:30 in invoke
• node_modules/regenerator-runtime/runtime.js:45:44 in tryCatch
• node_modules/regenerator-runtime/runtime.js:135:28 in invoke
• node_modules/regenerator-runtime/runtime.js:147:19 in Promise.resolve.then$argument_1
• node_modules/promise/setimmediate/core.js:37:14 in tryCallOne
• node_modules/promise/setimmediate/core.js:123:25 in setImmediate$argument_0
• node_modules/react-native/Libraries/Core/Timers/JSTimers.js:146:14 in _callTimer
• node_modules/react-native/Libraries/Core/Timers/JSTimers.js:194:17 in _callImmediatesPass
• node_modules/react-native/Libraries/Core/Timers/JSTimers.js:458:30 in callImmediates

• [native code]:null in callImmediates

• node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:407:6 in __callImmediates
• node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:143:6 in __guard$argument_0
• node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:384:10 in __guard
• node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:142:17 in __guard$argument_0

• [native code]:null in flushedQueue
• [native code]:null in callFunctionReturnFlushedQueue