How to reset packager cache
watchman watch-del-all
npm start -- --reset-cache
Deep reset packager cache
If the above doesn't work, try this:
watchman watch-del-all
rm -rf $TMPDIR/react-*
rm -rf $TMPDIR/metro-*
rm -rf $TMPDIR/haste-*
rm -rf $TMPDIR/npm-*
rm -rf node_modules
npm install
npm start -- --reset-cache
tip
If the above doesn't work, try restarting your computer.