null is not an object (evaluatin

或 Cannot read property 'DocumentDir' of undefined

1、npm install react-native-fetch-blob --save
2、react-native link react-native-fetch-blob --save

link完之后在ios工程目录Library下没找到。。

手动添加
1、 addFilesTo 选择node_modules->react-native-fetch-blob->ios->RNFetchBlob.xcodeproj
2、target->Linked Frameworks And Librarys 点击“+” 找到libRNFetchBlob
完成后clean 、run