old_contents: const linebot = require('../index.js');
  const express = require('express');
  
  const bot = linebot({
  	channelId: process.env.CHANNEL_ID,
  	ChannelSecret: process.env.CHANNEL_SECRET,
  	ChannelAccessToken: process.env.CHANNEL_ACCESS_TOKEN
  });
  
  const app = express();
  
  const linebotParser = bot.parser();
  
  app.post('/linewebhook', linebotParser);
  /*
  bot.on('message', function(event) {
    console.log(event); //把收到訊息的 event 印出來看看
  });
  
  const app = express();
  const linebotParser = bot.parser();
  app.post('/', linebotParser);
  
  //因為 express 預設走 port 3000，而 heroku 上預設卻不是，要透過下列程式轉換
  var server = app.listen(process.env.PORT || 8080, function() {
    var port = server.address().port;
    console.log("App now running on port", port);
  });
  */
  bot.on('message', function (event) {
  	event.reply(event.message.text).then(function (data) {
  		console.log('Success', data);
  	}).catch(function (error) {
  		console.log('Error', error);
  	});
  });
  
  app.listen(process.env.PORT || 8080, function () {
  	console.log('LineBot is running.');
  });
  
new_contents: const linebot = require('../index.js');
  const express = require('express');
  
  const bot = linebot({
  	channelId: process.env.CHANNEL_ID,
  	ChannelSecret: process.env.CHANNEL_SECRET,
  	ChannelAccessToken: process.env.CHANNEL_ACCESS_TOKEN
  });
  
  const app = express();
  
  const linebotParser = bot.parser();
  
  app.post('/linewebhook', linebotParser);
  /*
  bot.on('message', function(event) {
    console.log(event); //把收到訊息的 event 印出來看看
  });
  
  const app = express();
  const linebotParser = bot.parser();
  app.post('/', linebotParser);
  
  //因為 express 預設走 port 3000，而 heroku 上預設卻不是，要透過下列程式轉換
  var server = app.listen(process.env.PORT || 8080, function() {
    var port = server.address().port;
    console.log("App now running on port", port);
  });
  */
  bot.on('message', function (event) {
  	event.reply(event.message.text).then(function (data) {
  		console.log('Success', data);
  	}).catch(function (error) {
  		console.log('Error', error);
  	});
  });
  
  app.listen(process.env.PORT || 80, function () {
  	console.log('LineBot is running.');
  });
  
subject: Update echo-express.js