How do you detect the environment in an express.js app?

Question

How do you detect what environment an expressJS app is running in? (development, test, production?). There\'s nothing in process.env indicating an environment..

Answer 1

There are a lot of useful recommendations in other answers. I'm generally doing it like this:

const environment = process.env.NODE_ENV || 'development';

The good thing is that such approach is not specific to Express per se, but actually is an accepted practice in wider Node.js ecosystem.

Also, I've implemented a reusable module, which allows to automatically detect environment by analyzing both CLI arguments and NODE_ENV variable. This could be useful on your development machine, because you can easily change environment by passing a CLI argument to you Node.js program like this: $ node app.js --prod.

Please see more details and use cases on the detect-environment's page.

Answer 2

You can either check the environment by checking the app.settings.env (this will work in Express), or you can do it in a more direct way by checking process.env.NODE_ENV (the environment is the one found in that variable or 'development' by default < this also works in other libraries such as Socket.IO etc).

Answer 3

app.get('env') would also return the environment.

if ( app.get('env') === 'development' ) {
    app.use(express.errorHandler());
}

Answer 4

I'd like to address a straightforward way to passing NODE_ENV variables to your node script in order to access them in process.env

  "scripts": {
    "start": "./node_modules/.bin/cross-env NODE_ENV=development ./node_modules/.bin/nodemon server.js",
    "debug": "./node_modules/.bin/cross-env NODE_ENV=development ./node_modules/.bin/nodemon --debug server.js",
    "test": "./node_modules/.bin/cross-env NODE_ENV=test ./node_modules/.bin/babel-tape-runner test/test-*.js"
  },

can be used as

if ( app.get('env') === 'development' ) {
    app.use(express.errorHandler());
}

Answer 5

The can detect which environment you are in by inspecting app.settings.env.

Answer 6

cannot access the nodejs server. can detect node env from express using app.setting.env

1. var app = express();
2. app.setting.env render to the template engine.
3. check from the browser.