I am very excited about getting javascript coding on ios - however sitting and coding on an iPad is far from perfect 
Therefore I opened my script on my Mac using Microsoft VSCode, which works fine as scripts are saved to iCloud folder. Which can be opened on my desktop.
One thing missing then is: update the script on iOS device when the script file is updated from the desktop editor. To get the updates on iOS I need to close and open the script on my IOS device. So a feature request: Listen to iCloud file change events (if they exists)
/Sten