Realm-js: Build error from undefined symbols

[kevinnguy]

Not sure why I'm getting this error suddenly. Seems like the library isn't linking CocoaLumberjack but I'm not sure. Has anyone had this issue before?

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_DDLog", referenced from:
      objc-class-ref in libRealmReact.a(GCDWebServerMultiPartFormRequest.o)
      objc-class-ref in libRealmReact.a(GCDWebServerFileResponse.o)
      objc-class-ref in libRealmReact.a(GCDWebServerConnection.o)
      objc-class-ref in libRealmReact.a(GCDWebServerRequest.o)
      objc-class-ref in libRealmReact.a(GCDWebServer.o)
      objc-class-ref in libRealmReact.a(GCDWebServerFunctions.o)
ld: symbol(s) not found for architecture x86_64

I am on realm: 1.3.0

[kevinnguy]

Had to remove my DerivedData and build directories to fix this bug.

[haiifeng]

and i could not find out witch biuld directories, could you please tell me ?

[v-ken]

Few things that may help:

1. Make sure JavaScriptCore.framework is added to "Link Binary With Libraries" (https://stackoverflow.com/questions/54515175/undefined-symbols-for-architecture-arm64-jsclasscreate)
2. Product > Clean Build Folder
3. Remove project's DerivedData (File > Project Settings > Open DerivedData location)
4. Check that you are using a compatible React Native version with your Realm version - https://github.com/realm/realm-js/releases (Look for the last "Add support for React Native vX.XX")
5. react-native unlink realm and react-native link realm