skewer-mode

This is trivial in the right environments. Not shockingly, in emacs I get that. It actually takes a little getting used to at first, that up literally just moves the cursor up into the output of the previous command. Nowdays, it is severely restricting to have the same commands move the cursor that change the current command. (That is, left/right move cursor, up/down do a ton more in most terminals. That is not the case in emacs shells.) Really, though, the repl is a fun stepping stone to just sending function definitions from the file you are working on into an environment. https://github.com/skeeto/skewer-mode is a fun video showing the idea for javascript, amusingly. That said, there was a fun video a while back of the guy that did Minecraft live coding a video game. Basically, the game would be running, and he could make a chang

I wrote a somewhat similar tool for use with Emacs many years ago, SwankJS: https://github.com/swank-js/swank-js See this demo, for example: http://emacsrocks.com/e11.html It was not dependent on Chrome features and even did work with IE6 at some point. Too bad REPL-based programming is not very useful for modern JavaScript. There's a successor, though: https://github.com/skeeto/skewer-mode

Maybe you can use skewer-mode, probably not out of the box.. https://github.com/skeeto/skewer-mode/blob/master/README.md