Unable to exit REPL via escape codes when TERM=dumb

[silverwind]

^C or ^D do not exit the REPL when TERM=dumb is set. Is this expected?

$ TERM=dumb node
Welcome to Node.js v12.8.0.
Type ".help" for more information.
>
[press ^C]
(To exit, press ^C again or ^D or type .exit)
[press ^C]
>
[press ^D]
>
[press ^D]
>.exit
[finally out of it]

[bnoordhuis]

I don't think it's unexpected: the terminfo entry for 'dumb' basically says it doesn't support anything except ^G (bel).

On the other hand, lib/readline.js has some emulation baked in and teaching it about ^D isn't hard:

diff --git a/lib/readline.js b/lib/readline.js
index b741557a4d..1e7047ce1d 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -825,6 +825,9 @@ function _ttyWriteDumb(s, key) {
     }
   }
 
+  if (key.ctrl && key.name === 'd')
+    this.close();
+
   switch (key.name) {
     case 'return':  // Carriage return, i.e. \r
       this._sawReturnAt = Date.now();

The reason ^C doesn't work is because the first ^C leaves a \x03 character (the C in ^C) in the command buffer and that trips up this logic:

node/lib/repl.js

Lines 633 to 638 in 427e534

	const empty = self.line.length === 0;
	self.clearLine();
	_turnOffEditorMode(self);
	const cmd = self[kBufferedCommandSymbol];
	if (!(cmd && cmd.length > 0) && empty) {

[cjihrig]

This change in _ttyWriteDumb() fixes the Control+C issue. I'm not sure if it's correct.

diff --git a/lib/readline.js b/lib/readline.js
index b741557a4d..0606b63585 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -823,6 +823,8 @@ function _ttyWriteDumb(s, key) {
       // This readline instance is finished
       this.close();
     }
+
+    return;
   }
 
   switch (key.name) {

And, like Ben mentioned, the code doesn't currently support Control+D. It looks like it was never added in the original PR.

[legendecas]

Control+D would trigger end of stdin stream in most terminal, which has handled by readline.