Is there an IDE that does something similar to what is in this demo? I couldn’t find these features even in LightTable itself (seems they were originally planned but somehow lost/not documented) This sort of parallel view thing would be very helpful

which feature in particular @Josh Cho? the visual notebook style stuff has been picked up pretty well by https://observablehq.com/

@comma having the code duplicate on the right and auto-replacing variables with test variables and their results

Xcode Playgrounds do something like this for Swift https://www.appcoda.com/learnswift/playgrounds.html One of the use cases for my own app, Repla, is being able to do things like this in a separate app that you'd use side-by-side with your existing editor. https://repla.app/live-coding.html There's a Visual Studio Code plugin called Neuron that does something similar too https://blogs.msdn.microsoft.com/uk_faculty_connection/2018/10/29/data-science-in-visual-studio-code-using-neuron-a-new-vs-code-extension/

Light table itself has that, it's called the instarepl

@Josh Cho Just in case you haven't seen it, after Chris handed off Light Table to the community, he worked on a project called Eve that has other interesting ideas about juxtaposing the code and a live view of the data. Here's a nice overview of some of the prototypes they created: http://futureofcoding.org/essays/eve/

For js you have: https://quokkajs.com/ It has plugins for IntelliJ / VSCode as well. Has a free part / version.