Heroku keep crashing after Starting process with command `npm start' - node.js

Question

I am newbie. I am following Tutorial from https://www.sitepoint.com/building-facebook-chat-bot-node-heroku/ to make sample facebook messenger bot.
Just when I deployed it first time in heroku I got error
Here is my package.json
{
"name": "spbot",
"version": "1.0.0",
"description": "Testbot",
"main": "app.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"start": "node app.js"
},
"author": "Munkh",
"license": "ISC",
"dependencies": {
"body-parser": "^1.17.1",
"express": "^4.15.2",
"mongoose": "^4.9.1",
"request": "^2.81.0"
}
}
here is app.js
var express = require("express");
var request = require("request");
var bodyParser = require("body-parser");
var app = express();
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());
app.listen((process.env.PORT || 5000));
// Server index page
app.get("/", function (req, res) {
res.send("Deployed!");
});
// Facebook Webhook
// Used for verification
app.get("/webhook", function (req, res) {
if (req.query["hub.verify_token"] === "this_is_my_token") {
console.log("Verified webhook");
res.status(200).send(req.query["hub.challenge"]);
} else {
console.error("Verification failed. The tokens do not match.");
res.sendStatus(403);
}
});
I got error like this
2017-03-20T02:11:15.997279+00:00 heroku[web.1]: State changed from crashed to starting
2017-03-20T02:11:17.849748+00:00 heroku[web.1]: Starting process with command `npm start`
2017-03-20T02:11:20.455381+00:00 app[web.1]:
2017-03-20T02:11:20.455396+00:00 app[web.1]: > spbot#1.0.0 start /app
2017-03-20T02:11:20.455397+00:00 app[web.1]: > node app.js
2017-03-20T02:11:20.455397+00:00 app[web.1]:
2017-03-20T02:11:20.978077+00:00 heroku[web.1]: Process exited with status 0
2017-03-20T02:11:20.994169+00:00 heroku[web.1]: State changed from starting to crashed
2017-03-20T02:11:20.994986+00:00 heroku[web.1]: State changed from crashed to starting
2017-03-20T02:11:23.337790+00:00 heroku[web.1]: Starting process with command `npm start`
2017-03-20T02:11:27.660508+00:00 app[web.1]:
2017-03-20T02:11:27.660527+00:00 app[web.1]: > node app.js
2017-03-20T02:11:27.660526+00:00 app[web.1]: > spbot#1.0.0 start /app
2017-03-20T02:11:27.660528+00:00 app[web.1]:
2017-03-20T02:11:27.896343+00:00 heroku[web.1]: State changed from starting to crashed
2017-03-20T02:11:27.881546+00:00 heroku[web.1]: Process exited with status 0
Because error doesn't specify what went wrong and just keep crashing, I can't find a solution. My apologies if it is simple question.

Answer 1

You have to specify the node.js and npm version which you are using in package.json, as mentioned below.
Specify the versions which you are using in your development.
{
"name": "spbot",
"version": "1.0.0",
"description": "Testbot",
"main": "app.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"start": "node app.js"
},
"author": "Munkh",
"license": "ISC",
"dependencies": {
"body-parser": "^1.17.1",
"express": "^4.15.2",
"mongoose": "^4.9.1",
"request": "^2.81.0"
},
"engines": {
"node": "7.0.0",
"npm": "3.10.8"
}
}