In the past few years, we have covered plenty of iPhone IDEs for R, Python, and other developers. If Node.js is your thing, you may want to give play.js a look. It is a coding app for React Native and Node.js that lets you create and run local Node scripts without a computer. You will be able to manage projects with multiple files.
This Node.js iPhone app comes with code auto-completion, multi-file projects, and other convenient features. It costs under $4 at this time.[where to get it]