Add Libraries and fonts you are using , see in package.json and add these through Xcode
Xcode > YourProject > Build Phases > Link Binary with Libraries > Add here as shown in below pic link
Xcode > YourProject > Build Phases > Copy Bundle Resources > Add here as shown in below pic link
https://user-images.githubusercontent.com/1804003/27576120-92b6f830-5b4e-11e7-81da-c41500d673b3.png
https://cloud.githubusercontent.com/assets/378279/12421498/2db1f93a-be88-11e5-89c8-2e563ba6251a.png