fontFamily "helvatica" is not a system font and has not been loaded through Font.loadAsync. code example

Example: fontfamily "octicons" is not a system font and has not been loaded through font.loadasync.

fontfamily "octicons" is not a system font and has not been loaded through font.loadasync.
The fix for the above error would in 3 steps as following:
1. Delete node_modules folder from the root directory.
2. Delete package-lock.json file from the root directory of react-native project.
3. Run npm install from project directory.