set up enviroment variable on Heroku

heroku config:set key=value
heroku config
heroku config:unset key

Deployment to Heroku (using Heroku CLI)

//package.json
"scripts": {
 "start":"node path/to/your/app.js"
 },
//app.js
const port = process.env.PORT || 3000
const app = express()
... 
app.listen(port, () => {
 console.log('server up on port ' + port)
})

heroku login

heroku keys:add // add ssh public key to heroku

git init 
git add . 
git commit -m "your comment comes here"

heroku create your-project-name // create a project on heroku

heroku git:remote -a tecknovice-weather-server // add remote branch

heroku buildpacks:set heroku/nodejs //or any another language

git push heroku master //push code from local to remote branch

heroku logs --tail // for real time logging