Node.js, the difference between development and production
There is no difference between development and production in Node.js, i.e., there are no specific settings you need to apply to make Node.js work in a production configuration.
However, a few libraries in the npm registry recognize using the NODE_ENV variable and default it to a development setting.
Always run your Node.js with the NODE_ENV=production set.
A popular way of configuring your application is by using the twelve factor methodology.
Why is NODE_ENV considered an antipattern?
An environment is a digital platform or a system where engineers can build, test, deploy, and manage software products. Conventionally, there are four stages or types of environments where our application is run:
- Development
- Testing
- Staging
- Production
The fundamental problem of NODE_ENV stems from developers combining optimizations and software behavior with the environment their software is running on. The result is code like the following:
if (var process: NodeJS.Processprocess.NodeJS.Process.env: NodeJS.ProcessEnvThe `process.env` property returns an object containing the user environment.
See [`environ(7)`](http://man7.org/linux/man-pages/man7/environ.7.html).
An example of this object looks like:
```js
{
TERM: 'xterm-256color',
SHELL: '/usr/local/bin/bash',
USER: 'maciej',
PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin',
PWD: '/Users/maciej',
EDITOR: 'vim',
SHLVL: '1',
HOME: '/Users/maciej',
LOGNAME: 'maciej',
_: '/usr/local/bin/node'
}
```
It is possible to modify this object, but such modifications will not be
reflected outside the Node.js process, or (unless explicitly requested)
to other `Worker` threads.
In other words, the following example would not work:
```bash
node -e 'process.env.foo = "bar"' && echo $foo
```
While the following will:
```js
import { env } from 'node:process';
env.foo = 'bar';
console.log(env.foo);
```
Assigning a property on `process.env` will implicitly convert the value
to a string. **This behavior is deprecated.** Future versions of Node.js may
throw an error when the value is not a string, number, or boolean.
```js
import { env } from 'node:process';
env.test = null;
console.log(env.test);
// => 'null'
env.test = undefined;
console.log(env.test);
// => 'undefined'
```
Use `delete` to delete a property from `process.env`.
```js
import { env } from 'node:process';
env.TEST = 1;
delete env.TEST;
console.log(env.TEST);
// => undefined
```
On Windows operating systems, environment variables are case-insensitive.
```js
import { env } from 'node:process';
env.TEST = 1;
console.log(env.test);
// => 1
```
Unless explicitly specified when creating a `Worker` instance,
each `Worker` thread has its own copy of `process.env`, based on its
parent thread's `process.env`, or whatever was specified as the `env` option
to the `Worker` constructor. Changes to `process.env` will not be visible
across `Worker` threads, and only the main thread can make changes that
are visible to the operating system or to native add-ons. On Windows, a copy of `process.env` on a `Worker` instance operates in a case-sensitive manner
unlike the main thread.env.string | undefinedNODE_ENV === 'development') {
// ...
}
if (var process: NodeJS.Processprocess.NodeJS.Process.env: NodeJS.ProcessEnvThe `process.env` property returns an object containing the user environment.
See [`environ(7)`](http://man7.org/linux/man-pages/man7/environ.7.html).
An example of this object looks like:
```js
{
TERM: 'xterm-256color',
SHELL: '/usr/local/bin/bash',
USER: 'maciej',
PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin',
PWD: '/Users/maciej',
EDITOR: 'vim',
SHLVL: '1',
HOME: '/Users/maciej',
LOGNAME: 'maciej',
_: '/usr/local/bin/node'
}
```
It is possible to modify this object, but such modifications will not be
reflected outside the Node.js process, or (unless explicitly requested)
to other `Worker` threads.
In other words, the following example would not work:
```bash
node -e 'process.env.foo = "bar"' && echo $foo
```
While the following will:
```js
import { env } from 'node:process';
env.foo = 'bar';
console.log(env.foo);
```
Assigning a property on `process.env` will implicitly convert the value
to a string. **This behavior is deprecated.** Future versions of Node.js may
throw an error when the value is not a string, number, or boolean.
```js
import { env } from 'node:process';
env.test = null;
console.log(env.test);
// => 'null'
env.test = undefined;
console.log(env.test);
// => 'undefined'
```
Use `delete` to delete a property from `process.env`.
```js
import { env } from 'node:process';
env.TEST = 1;
delete env.TEST;
console.log(env.TEST);
// => undefined
```
On Windows operating systems, environment variables are case-insensitive.
```js
import { env } from 'node:process';
env.TEST = 1;
console.log(env.test);
// => 1
```
Unless explicitly specified when creating a `Worker` instance,
each `Worker` thread has its own copy of `process.env`, based on its
parent thread's `process.env`, or whatever was specified as the `env` option
to the `Worker` constructor. Changes to `process.env` will not be visible
across `Worker` threads, and only the main thread can make changes that
are visible to the operating system or to native add-ons. On Windows, a copy of `process.env` on a `Worker` instance operates in a case-sensitive manner
unlike the main thread.env.string | undefinedNODE_ENV === 'production') {
// ...
}
if (['production', 'staging'].Array<string>.includes(searchElement: string, fromIndex?: number): booleanDetermines whether an array includes a certain element, returning true or false as appropriate.includes(var process: NodeJS.Processprocess.NodeJS.Process.env: NodeJS.ProcessEnvThe `process.env` property returns an object containing the user environment.
See [`environ(7)`](http://man7.org/linux/man-pages/man7/environ.7.html).
An example of this object looks like:
```js
{
TERM: 'xterm-256color',
SHELL: '/usr/local/bin/bash',
USER: 'maciej',
PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin',
PWD: '/Users/maciej',
EDITOR: 'vim',
SHLVL: '1',
HOME: '/Users/maciej',
LOGNAME: 'maciej',
_: '/usr/local/bin/node'
}
```
It is possible to modify this object, but such modifications will not be
reflected outside the Node.js process, or (unless explicitly requested)
to other `Worker` threads.
In other words, the following example would not work:
```bash
node -e 'process.env.foo = "bar"' && echo $foo
```
While the following will:
```js
import { env } from 'node:process';
env.foo = 'bar';
console.log(env.foo);
```
Assigning a property on `process.env` will implicitly convert the value
to a string. **This behavior is deprecated.** Future versions of Node.js may
throw an error when the value is not a string, number, or boolean.
```js
import { env } from 'node:process';
env.test = null;
console.log(env.test);
// => 'null'
env.test = undefined;
console.log(env.test);
// => 'undefined'
```
Use `delete` to delete a property from `process.env`.
```js
import { env } from 'node:process';
env.TEST = 1;
delete env.TEST;
console.log(env.TEST);
// => undefined
```
On Windows operating systems, environment variables are case-insensitive.
```js
import { env } from 'node:process';
env.TEST = 1;
console.log(env.test);
// => 1
```
Unless explicitly specified when creating a `Worker` instance,
each `Worker` thread has its own copy of `process.env`, based on its
parent thread's `process.env`, or whatever was specified as the `env` option
to the `Worker` constructor. Changes to `process.env` will not be visible
across `Worker` threads, and only the main thread can make changes that
are visible to the operating system or to native add-ons. On Windows, a copy of `process.env` on a `Worker` instance operates in a case-sensitive manner
unlike the main thread.env.string | undefinedNODE_ENV)) {
// ...
}
While this might look harmless, it makes the production and staging environments different, thus making reliable testing impossible. For example a test and thus a functionality of your product could pass when NODE_ENV is set to development but fail when setting NODE_ENV to production.
Therefore, setting NODE_ENV to anything but production is considered an antipattern.