readline: use removeListener event

use removeListener event rather than checking listeners().length every `data` event

Author: adammw

lib/readline.js

@@ -804,24 +804,29 @@ function emitKeypressEvents(stream) {
   stream._emitKeypress = true;
 
   function onData(b) {
-    if (stream.listeners('keypress').length > 0) {
-      emitKey(stream, b);
-    } else {
-      // Nobody's watching anyway
-      stream.removeListener('data', onData);
-      stream.on('newListener', onNewListener);
-    }
+    emitKey(stream, b);
   }
 
   function onNewListener(event) {
     if (event == 'keypress') {
       stream.on('data', onData);
+      stream.on('removeListener', onRemovedListener);
       stream.removeListener('newListener', onNewListener);
     }
   }
+ 
+  function onRemovedListener(event) {
+    if (event == 'keypress' && stream.listeners('keypress').length == 0) {
+      // Nobody's watching anyway
+      stream.removeListener('data', onData);
+      stream.removeListener('removeListener', onRemovedListener);
+      stream.on('newListener', onNewListener);
+    }
+  }
 
   if (stream.listeners('keypress').length > 0) {
     stream.on('data', onData);
+    stream.on('removeListener', onRemovedListener);
   } else {
     stream.on('newListener', onNewListener);
   }