[refactor] Deduplicate listeners

app.js

@@ -1,13 +1,21 @@
+// Internal
 const { spawn } = require('child_process');
 const { EOL } = require('os');
 const os = require('os');
 
+// Modules
 const Telegraf = require('telegraf');
-const { path } = require('./util/index.js');
 
+//Config
 const config = require('./config.js');
-const validator = require('./lib/validator');
+
+// Utils
+const { path } = require('./util/index.js');
+
+// Lib
+const validator = require('./lib/validator.js');
 const responder = require('./lib/responseHandler.js');
+const listeners = require('./lib/listeners.js');
 
 const dateOptions = {
 	weekday: 'long',
@@ -40,11 +48,9 @@ bot.command('start',
 		const newProc = spawn(defaultShell, {
 			cwd: home
 		});
-		newProc.stdout.setEncoding('utf8');
 		sessions.push(newProc);
 		sessions.currentSession = newProc;
-		sessions.currentSession.stdout.on('data', d => responder.success(d)(ctx));
-		sessions.currentSession.stderr.on('data', e => responder.success(e)(ctx));
+		listeners.add(sessions.currentSession, responder, ctx);
 		return ctx.replyWithHTML(`Welcome to tsh -- <code>Telegram Shell!</code>\n\n`
 			+ `You are now connected to <code>${hostname}</code>`
 			+ ` as <strong>${username}</strong>`);
@@ -64,8 +70,7 @@ bot.command('attach',
 		if(Number.isNaN(sessionIndex) || !sessions[sessionIndex])
 			return responder.fail('Session not found. /ls for list of sessions')(ctx);
 		sessions.currentSession = sessions[sessionIndex];
-		sessions.currentSession.stdout.on('data', d => responder.success(d)(ctx));
-		sessions.currentSession.stderr.on('data', e => responder.success(e)(ctx));
+		listeners.add(sessions.currentSession, responder, ctx);
 		return responder.success(`Reattached to shell ${sessionIndex}`)(ctx);
 	});
 
@@ -78,8 +83,7 @@ bot.command('detach',
 				? sessions.currentSession : sessions[sessionIndex];
 		if(!currentSession)
 			return responder.fail('Session not found. /ls for list of sessions.')(ctx);
-		sessions.currentSession.stdout.removeAllListeners('data');
-		sessions.currentSession.stderr.removeAllListeners('data');
+		listeners.remove(sessions.currentSession);
 		sessions.currentSession = undefined;
 		return responder.success(`Detached from shell ${sessionIndex}`)(ctx);
 	});

lib/listeners.js

@@ -0,0 +1,16 @@
+const addListeners = (emitter, responder, ctx) => {
+	emitter.stdout.setEncoding('utf8');
+	emitter.stderr.setEncoding('utf8');
+	emitter.stdout.on('data', d => responder.success(d)(ctx));
+	emitter.stderr.on('data', e => responder.success(e)(ctx));
+};
+
+const removeListeners = emitter => {
+	emitter.stdout.removeAllListeners('data');
+	emitter.stderr.removeAllListeners('data');
+};
+
+module.exports = {
+	add: addListeners,
+	remove: removeListeners,
+};