How to Regenerate iOS Folder in React Native Project

How can I regenerate ios folder in React Native project?

The process you need to follow is so similar to renaming a react native app. Basically you just need to run react-native upgrade in your root project directory. For further info you can check another question here. The instructions below explains how to create another react native project based on a copied one with a new name.

First copy the directory which your to-be-name-changed application exists. And go to your newly cloned directory.
Change the name at index.ios/android.js file which is given as a parameter to AppRegistry.
Change the name and version accordingly on package.json
Delete /ios and /android folders which are remaining from your older app.
Run $react-native upgrade to generate /ios and /android folders again.
Run $react-native link for any native dependency.
Finally run $react-native run-ios or anything you want.

Re-create iOS folder in react-native project

Code 65 don't give too much information... Code 65

the best thing you can show us is the stack trace of logs from the terminal or xCode

If you want to delete all dependencies / android / ios folders npx react-native-clean-project command inside root of your rn project

documentation of react-native-clean-project

React native, recreate ios and android folders

As mentioned in the comments,
If you are using Expo as your development tool for react native, you can always reset the android and ios folders by running:

expo eject

from the command line when ever you need, just notice it will override changes made directly on these folders, so eject cerfully.

How can I regenerate Android and IOS folders in React Native project version 0.61.x?

you cant regenerate once you have built android and ios modules using react-native init myProjectName.you have to remove everything in the first and built one again

Unable to see Android/iOS Folder in react native project

Running following commands should do the trick:

sudo rm -rf android/ ios/ #Delete Android and ios folders first...
react-native eject
react-native upgrade //rebuilds android/ios folders
react-native link
react-native run-android
react-native run-ios