You're an avid KDE user
You've been using tools like RunJS to try things out, fix bugs, format text, et cetera, but...
- you think Electron should die in a fire,
- you want to use FLOSS tools where at all possible,
- ...and you don't really need all sorts of fancy features anyway.

Well, here you go, friend. This quick and dirty .desktop file creates repl.js in the liminal space that is your /tmp/ directory, opens it in KWrite, and opens up a Konsole window that watches /tmp/repl.js for changes and runs them in node using nodemon (IE, gives you a barebones JavaScript REPL).

Screenshot:

Requirements:

A GNU/Linux distro with KWrite, Konsole, and Node installed

Setup:

Install nodemon

npm i -g nodemon

Drop JSRepl.js wherever it needs to live on your system

cd /my/applications/dir && wget https://raw.githubusercontent.com/N-Upchurch/JSRepl.desktop/main/JSRepl.desktop

Use:

Open your application launcher and click on JSRepl to launch
Write code
Save to run your code (or if you're really fancy, and brave, turn on autosave in KWrite)

FAQs:

Does it work with TypeScript?
- My guy, if I wanted types I'd learn a real programming language.
Does it have X feature?
- Probably not; it's just a .desktop file. Feel free to submit a PR if you have ideas.
Do I have to use KWrite and Konsole?
- Not if you change the program names in JSRepl.desktop, but you're on your own.