Hi! Please clarify how to use this mistery link in each repl?
When I press "Open in a new tab" it opens REPL in new browser tab as I expected. But then just started to run my project and then end with "This repl has exited, run again?".
But I expect to stay in that REPL as it is normally done in REPL languages (Clojure, Node, Python etc). Is there a way for such behaviour?
Well, the repl will "exit" if it gets to the last line of code. That's just because it's done doing everything you've asked it to do.
Simply click the "run again" button if you want to rerun the program from the top.
If you want to keep a program from terminating then consider using some kind of loop.