dotenv
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    16.0.3 • Public • Published

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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 Featured on Openbase Limited Edition Tee Original Limited Edition Tee Redacted

    Install

    # install locally (recommended)
    npm install dotenv --save

    Or installing with yarn? yarn add dotenv

    Usage

    Create a .env file in the root of your project:

    S3_BUCKET="YOURS3BUCKET"
    SECRET_KEY="YOURSECRETKEYGOESHERE"

    As early as possible in your application, import and configure dotenv:

    require('dotenv').config()
    console.log(process.env) // remove this after you've confirmed it is working

    .. or using ES6?

    import * as dotenv from 'dotenv' // see https://github.com/motdotla/dotenv#how-do-i-use-dotenv-with-import
    dotenv.config()
    import express from 'express'

    That's it. process.env now has the keys and values you defined in your .env file:

    require('dotenv').config()
    
    ...
    
    s3.getBucketCors({Bucket: process.env.S3_BUCKET}, function(err, data) {})

    Multiline values

    If you need multiline variables, for example private keys, those are now supported (>= v15.0.0) with line breaks:

    PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----
    ...
    Kh9NV...
    ...
    -----END RSA PRIVATE KEY-----"

    Alternatively, you can double quote strings and use the \n character:

    PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----\nKh9NV...\n-----END RSA PRIVATE KEY-----\n"

    Comments

    Comments may be added to your file on their own line or inline:

    # This is a comment
    SECRET_KEY=YOURSECRETKEYGOESHERE # comment
    SECRET_HASH="something-with-a-#-hash"

    Comments begin where a # exists, so if your value contains a # please wrap it in quotes. This is a breaking change from >= v15.0.0 and on.

    Parsing

    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' }

    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.

    $ node -r dotenv/config your_script.js

    The configuration options below are supported as command line arguments in the format dotenv_config_<option>=value

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

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

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

    Variable Expansion

    You need to add the value of another variable in one of your variables? Use dotenv-expand.

    Syncing

    You need to keep .env files in sync between machines, environments, or team members? Use dotenv-vault.

    Examples

    See examples of using dotenv with various frameworks, languages, and configurations.

    Documentation

    Dotenv exposes two functions:

    • config
    • parse

    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')

    Specify a custom path if your file containing environment variables is located elsewhere.

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

    Default: utf8

    Specify the encoding of your file containing environment variables.

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

    Default: false

    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 })
    Override

    Default: false

    Override any environment variables that have already been set on your machine with values from your .env file.

    require('dotenv').config({ override: true })

    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

    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

    FAQ

    Why is the .env file not loading my environment variables successfully?

    Most likely your .env file is not in the correct place. See this stack overflow.

    Turn on debug mode and try again..

    require('dotenv').config({ debug: true })

    You will receive a helpful error outputted to your console.

    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 rules does the parsing engine follow?

    The parsing engine currently supports the following rules:

    • BASIC=basic becomes {BASIC: 'basic'}
    • empty lines are skipped
    • lines beginning with # are treated as comments
    • # marks the beginning of a comment (unless when the value is wrapped in quotes)
    • 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'}
    
    • backticks are supported (BACKTICK_KEY=`This has 'single' and "double" quotes inside of it.`)

    What happens to environment variables that were already set?

    By default, 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.

    If instead, you want to override process.env use the override option.

    require('dotenv').config({ override: true })

    How come my environment variables are not showing up for React?

    Your React code is run in Webpack, where the fs module or even the process global itself are not accessible out-of-the-box. process.env can only be injected through Webpack configuration.

    If you are using react-scripts, which is distributed through create-react-app, it has dotenv built in but with a quirk. Preface your environment variables with REACT_APP_. See this stack overflow for more details.

    If you are using other frameworks (e.g. Next.js, Gatsby...), you need to consult their documentation for how to inject environment variables into the client.

    Can I customize/write plugins for dotenv?

    Yes! dotenv.config() 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)

    How do I use dotenv with import?

    Simply..

    // index.mjs (ESM)
    import * as dotenv from 'dotenv' // see https://github.com/motdotla/dotenv#how-do-i-use-dotenv-with-import
    dotenv.config()
    import express from 'express'

    A little background..

    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

    What does this mean in plain language? It means you would think the following would work but it won't.

    // errorReporter.mjs
    import { Client } from 'best-error-reporting-service'
    
    export default new Client(process.env.API_KEY)
    
    // index.mjs
    import dotenv from 'dotenv'
    dotenv.config()
    
    import errorReporter from './errorReporter.mjs'
    errorReporter.report(new Error('documented example'))

    process.env.API_KEY will be blank.

    Instead the above code should be written as..

    // errorReporter.mjs
    import { Client } from 'best-error-reporting-service'
    
    export default new Client(process.env.API_KEY)
    
    // index.mjs
    import * as dotenv from 'dotenv'
    dotenv.config()
    
    import errorReporter from './errorReporter.mjs'
    errorReporter.report(new Error('documented example'))

    Does that make sense? It's a bit unintuitive, but it is how importing of ES6 modules work. Here is a working example of this pitfall.

    There are two alternatives to this approach:

    1. Preload dotenv: node --require dotenv/config index.js (Note: you do not need to import dotenv with this approach)
    2. Create a separate file that will execute config first as outlined in this comment on #133

    What about variable expansion?

    Try dotenv-expand

    What about syncing and securing .env files?

    Use dotenv-vault

    Contributing Guide

    See CONTRIBUTING.md

    CHANGELOG

    See CHANGELOG.md

    Who's using dotenv?

    These npm modules depend on it.

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

    Dependencies (0)

      Dev Dependencies (10)

      Install

      npm i dotenv

      DownloadsWeekly Downloads

      30,363,041

      Version

      16.0.3

      License

      BSD-2-Clause

      Unpacked Size

      36.6 kB

      Total Files

      10

      Last publish

      Collaborators

      • ~jcblw
      • scottmotte
      • motdotla