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motdotla
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Description

Loads environment variables from .env for nodejs projects.

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dotenv

dotenv

Dotenv is a zero-dependency module that loads environment variables from a

.env
file into
process.env
. Storing configuration in the environment separate from code is based on The Twelve-Factor App methodology.

BuildStatus Build status NPM version js-standard-style Coverage Status LICENSE Conventional Commits

Install

# with npm
npm install dotenv

or with Yarn

yarn add dotenv

Usage

As early as possible in your application, require and configure dotenv.

require('dotenv').config()

Create a

.env
file in the root directory of your project. Add environment-specific variables on new lines in the form of
NAME=VALUE
. For example:
DB_HOST=localhost
DB_USER=root
DB_PASS=s1mpl3

process.env
now has the keys and values you defined in your
.env
file.
const db = require('db')
db.connect({
  host: process.env.DB_HOST,
  username: process.env.DB_USER,
  password: process.env.DB_PASS
})

Preload

You can use the

--require
(
-r
) command line option to preload dotenv. By doing this, you do not need to require and load dotenv in your application code. This is the preferred approach when using
import
instead of
require
.
$ node -r dotenv/config your_script.js

The configuration options below are supported as command line arguments in the format

dotenv_config_=value
$ node -r dotenv/config your_script.js dotenv_config_path=/custom/path/to/.env

Additionally, you can use environment variables to set configuration options. Command line arguments will precede these.

$ DOTENV_CONFIG_=value node -r dotenv/config your_script.js
$ DOTENV_CONFIG_ENCODING=latin1 node -r dotenv/config your_script.js dotenv_config_path=/custom/path/to/.env

Config

config
will read your
.env
file, parse the contents, assign it to
process.env
, and return an Object with a
parsed
key containing the loaded content or an
error
key if it failed.
const result = dotenv.config()

if (result.error) { throw result.error }

console.log(result.parsed)

You can additionally, pass options to

config
.

Options

Path

Default:

path.resolve(process.cwd(), '.env')

You may specify a custom path if your file containing environment variables is located elsewhere.

require('dotenv').config({ path: '/custom/path/to/.env' })

Encoding

Default:

utf8

You may specify the encoding of your file containing environment variables.

require('dotenv').config({ encoding: 'latin1' })

Debug

Default:

false

You may turn on logging to help debug why certain keys or values are not being set as you expect.

require('dotenv').config({ debug: process.env.DEBUG })

Parse

The engine which parses the contents of your file containing environment variables is available to use. It accepts a String or Buffer and will return an Object with the parsed keys and values.

const dotenv = require('dotenv')
const buf = Buffer.from('BASIC=basic')
const config = dotenv.parse(buf) // will return an object
console.log(typeof config, config) // object { BASIC : 'basic' }

Options

Debug

Default:

false

You may turn on logging to help debug why certain keys or values are not being set as you expect.

const dotenv = require('dotenv')
const buf = Buffer.from('hello world')
const opt = { debug: true }
const config = dotenv.parse(buf, opt)
// expect a debug message because the buffer is not in KEY=VAL form

Rules

The parsing engine currently supports the following rules:

  • BASIC=basic
    becomes
    {BASIC: 'basic'}
  • empty lines are skipped
  • lines beginning with
    #
    are treated as comments
  • empty values become empty strings (
    EMPTY=
    becomes
    {EMPTY: ''}
    )
  • inner quotes are maintained (think JSON) (
    JSON={"foo": "bar"}
    becomes
    {JSON:"{\"foo\": \"bar\"}"
    )
  • whitespace is removed from both ends of unquoted values (see more on
    trim
    ) (
    FOO=  some value
    becomes
    {FOO: 'some value'}
    )
  • single and double quoted values are escaped (
    SINGLE_QUOTE='quoted'
    becomes
    {SINGLE_QUOTE: "quoted"}
    )
  • single and double quoted values maintain whitespace from both ends (
    FOO="  some value  "
    becomes
    {FOO: '  some value  '}
    )
  • double quoted values expand new lines (
    MULTILINE="new\nline"
    becomes
{MULTILINE: 'new
line'}

FAQ

Should I commit my
.env
file?

No. We strongly recommend against committing your

.env
file to version control. It should only include environment-specific values such as database passwords or API keys. Your production database should have a different password than your development database.

Should I have multiple
.env
files?

No. We strongly recommend against having a "main"

.env
file and an "environment"
.env
file like
.env.test
. Your config should vary between deploys, and you should not be sharing values between environments.

In a twelve-factor app, env vars are granular controls, each fully orthogonal to other env vars. They are never grouped together as “environments”, but instead are independently managed for each deploy. This is a model that scales up smoothly as the app naturally expands into more deploys over its lifetime.

The Twelve-Factor App

What happens to environment variables that were already set?

We will never modify any environment variables that have already been set. In particular, if there is a variable in your

.env
file which collides with one that already exists in your environment, then that variable will be skipped. This behavior allows you to override all
.env
configurations with a machine-specific environment, although it is not recommended.

If you want to override

process.env
you can do something like this:
const fs = require('fs')
const dotenv = require('dotenv')
const envConfig = dotenv.parse(fs.readFileSync('.env.override'))
for (const k in envConfig) {
  process.env[k] = envConfig[k]
}

Can I customize/write plugins for dotenv?

For

[email protected]
: Yes.
dotenv.config()
now returns an object representing the parsed
.env
file. This gives you everything you need to continue setting values on
process.env
. For example:
const dotenv = require('dotenv')
const variableExpansion = require('dotenv-expand')
const myEnv = dotenv.config()
variableExpansion(myEnv)

What about variable expansion?

Try dotenv-expand

How do I use dotenv with
import
?

ES2015 and beyond offers modules that allow you to

export
any top-level
function
,
class
,
var
,
let
, or
const
.

When you run a module containing an

import
declaration, the modules it imports are loaded first, then each module body is executed in a depth-first traversal of the dependency graph, avoiding cycles by skipping anything already executed.

ES6 In Depth: Modules

You must run

dotenv.config()
before referencing any environment variables. Here's an example of problematic code:

errorReporter.js
:
import { Client } from 'best-error-reporting-service'

export const client = new Client(process.env.BEST_API_KEY)

index.js
:
import dotenv from 'dotenv'
import errorReporter from './errorReporter'

dotenv.config() errorReporter.client.report(new Error('faq example'))

client
will not be configured correctly because it was constructed before
dotenv.config()
was executed. There are (at least) 3 ways to make this work.
  1. Preload dotenv:
    node --require dotenv/config index.js
    (Note: you do not need to
    import
    dotenv with this approach
    )
  2. Import
    dotenv/config
    instead of
    dotenv
    (Note: you do not need to call
    dotenv.config()
    and must pass options via the command line or environment variables with this approach
    )
  3. Create a separate file that will execute
    config
    first as outlined in this comment on #133

Contributing Guide

See CONTRIBUTING.md

Change Log

See CHANGELOG.md

Who's using dotenv?

These npm modules depend on it.

Projects that expand it often use the keyword "dotenv" on npm.

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