https://github.com/facebook/react-native/issues/17618,
自测解决办法：
原因是react-native版本 0.52.1的原因，将版本降为0.51.0
Simply downgrading to React-Native 0.51.0 (by just runningnpm i -S react-native@0.51.0seems to fix the issue).
Remember that, after downgrading, you should also reset the cache:
watchman watch-del-all
npm run start -- --reset-cache
