React Native deletes the iOS and Android folders and resets them

Start by deleting the iOS and Android folders, or better yet, backing them up under a different name. Then use the terminal to access the project root directory. React-native upgrade — Legacy True and then connect to react-Native Link. If you add something manually, for example using iconFont, you need to add it again manually. If there are problems with the dependency library, remove the node_modules folder and then NPM install.