title: Post is not defined in nodejs
body: <p>I am using Google cloud vm instance to run my node app and i have installed Ubuntu 16.04.6 i have nodejs v11.10.1 installed and npm v6.7.0 installed but when i run app using <code>node app</code> it shows <code>ReferenceError: post is not defined</code>.I don't know what is wrong here.</p>
  
  <p>Here is my package.json file:</p>
  
  <pre><code>{"name": "name",
   "version": "1.0.0",
   "description": "",
   "main": "app.js",
   "scripts": {
   "start": "node app.js",
   "deploy":"gcloud app deploy"
  },
   "author": "Faiz Khan",
   "license": "ISC",
   "dependencies": {
   "bson": "^4.0.1",
   "connect-mongo": "^2.0.3",
   "ejs": "^2.6.1",
   "express": "^4.16.3",
   "express-session": "^1.15.6",
   "fabric": "^2.4.4",
   "jquery": "^3.3.1",
   "mongodb": "^2.2.33",
   "mysql": "^2.16.0",
   "node-fetch": "^2.3.0",
   "npm": "^6.4.1",
   "redis": "^2.8.0",
   "socket.io": "^2.0.3"
  }
  }
  </code></pre>
  
  <p>Here is my post route:</p>
  
  <pre><code>app.post('/chat',(req,res,next) =&gt;{
  userName = req.body.usrnm.toUpperCase();  
  res.render('classLayout',{user:userName});
  });
  </code></pre>
  
  <p>Here is error:</p>
  
  <pre><code>ReferenceError: post is not defined
  at app.post (/home/equalsignlearning/redis_op/app.js:104:10)
  at Layer.handle [as handle_request] (/home/equalsignlearning/redis_op/node_modules/express/lib/router/layer.js:95:5)
  at next (/home/equalsignlearning/redis_op/node_modules/express/lib/router/route.js:137:13)
  at Route.dispatch (/home/equalsignlearning/redis_op/node_modules/express/lib/router/route.js:112:3)
  at Layer.handle [as handle_request] (/home/equalsignlearning/redis_op/node_modules/express/lib/router/layer.js:95:5)
  at /home/equalsignlearning/redis_op/node_modules/express/lib/router/index.js:281:22
  at Function.process_params (/home/equalsignlearning/redis_op/node_modules/express/lib/router/index.js:335:12)
  at next (/home/equalsignlearning/redis_op/node_modules/express/lib/router/index.js:275:10)
  at jsonParser (/home/equalsignlearning/redis_op/node_modules/body-parser/lib/types/json.js:101:7)
  at Layer.handle [as handle_request] (/home/equalsignlearning/redis_op/node_modules/express/lib/router/layer.js:95:5)
  </code></pre>
  
  <p>The app works fine on localhost on macos and even on heroku but it only creates problem on ubuntu</p>