[dmitry-vsl]

>> you can use print statements and step debugging, together, at any point in time in the recording

I am working on something similar. I am building an IDE that allows to jump from the line printed by a console.log call to a corresponding code location, and observe variables and intermediate expressions.

It also displays a dynamic calltree of a program, allowing to navigate it in a time-travel manner.

Currently it only supports pure functional subset of JavaScript, but I am working on support for imperative programming (mutating data in place).

https://leporello.tech/