Why is process.env.NODE_ENV undefined?
process.env
is a reference to your environment, so you have to set the variable there.
To set an environment variable in Windows:
SET NODE_ENV=development
on macOS / OS X or Linux:
export NODE_ENV=development
tips
in package.json
:
"scripts": {
"start": "set NODE_ENV=dev && node app.js"
}
in app.js
:
console.log(process.env.NODE_ENV) // dev
console.log(process.env.NODE_ENV === 'dev') // false
console.log(process.env.NODE_ENV.length) // 4 (including a space at the end)
so, this may better:
"start": "set NODE_ENV=dev&& node app.js"
or
console.log(process.env.NODE_ENV.trim() === 'dev') // true
For people using *nix (Linux, OS X, etc.), there's no reason to do it via a second export command, you can chain it as part of the invoking command:
NODE_ENV=development node server.js
Easier, no? :)