/Javascript/Node.js/Node process.env.PORT

Node process.env.PORT

In many environments (e.g. Heroku), and as a convention, 
you can set the environment variable PORT 
to tell your web server what port to listen on.

So `process.env.PORT || 3000` means: 
whatever is in the environment variable PORT, 
or 3000 if there's nothing there.

So you pass that to app.listen, 
or to app.set('port', ...), 
and that makes your server able to accept a 
"what port to listen on" parameter from the environment.

If you pass 3000 hard-coded to app.listen(), 
you're always listening on port 3000, 
which might be just for you, or not, 
depending on your requirements and the requirements of the environment 
in which you're running your server.

Source: stackoverflow.com

Similar codes

7 votes110 views1 answer
Node require module
Javascript Node.js
16 votes111 views3 answers
How to create a folder using fs in node js
Javascript Node.js
0 vote126 views1 answer
Nodejs how to send html
Javascript Node.js
1 vote128 views1 answer
Nodejs aws s3 bucket delete item
Javascript Node.js
0 vote120 views1 answer
How to fetch first 10 characters of a string in node js
Javascript Node.js
8 votes107 views1 answer
How to split index.js to routes nodejs
Javascript Node.js
1 vote122 views1 answer
Nodejs download image from url
Javascript Node.js
7 votes112 views1 answer
Path.basename nodejs
Javascript Node.js
2 votes63 views2 answers
Error: node sass version 6.0.0 is incompatible with ^4.0.0 || ^5.0.0.
Javascript Node.js
21 votes125 views2 answers
Nodejs check if file is running on server or client
Javascript Node.js