Question

Is there any way to trigger a function that’s called when the user types .exit or [Ctrl][D]s the script?

Something like:

repl.start().on('exit', function() {
    console.log("Thanks for using customized Node REPL!");
});

(Except, of course, I’d actually put useful code instead of the console.log.)

Answer 1

repl.start().rli.on('close', function() {
    console.log("Thanks for using customized Node REPL!");
}); 

REPL uses the Readline module, which emits a Close event. From the docs:

Event: ‘close’

function () {}

Emitted whenever the in stream receives a ^C or ^D, respectively known
as SIGINT and EOT. This is a good way to know the user is finished
using your program.