The dotenv npm package is used to load environment variables from a .env file into process.env, providing a convenient way to configure your application's environment during development. It helps in managing sensitive credentials and configuration options by keeping them out of the codebase.
Basic Configuration
This is the simplest use case for dotenv. By calling `require('dotenv').config();`, dotenv reads the .env file, parses the contents, and loads them into `process.env`. After this, environment variables can be accessed using `process.env.VAR_NAME`.
require('dotenv').config();Custom Path
If your .env file is not located in the root directory or you have multiple .env files, you can specify a custom path to your .env file using the `path` option.
require('dotenv').config({ path: '/custom/path/to/.env' });Debugging
To assist in debugging, you can enable debug output by setting the `debug` option to `true`. This will log any errors to the console while reading the .env file.
require('dotenv').config({ debug: process.env.DEBUG });dotenv-expand is an extension for dotenv. It allows you to have environment variables in your .env file that reference other environment variables, similar to variable expansion in Unix shell scripts. It's useful when you need to reduce redundancy in your .env files.
cross-env allows you to set and use environment variables across platforms without worrying about platform-specific differences in how environment variables are set. Unlike dotenv, which is focused on loading variables from a file, cross-env is more about providing scripts with environment variables in a cross-platform way.
env-cmd is another npm package that allows you to specify a file containing environment variable definitions and then run a given command using those variables. It's similar to dotenv but is more focused on injecting environment variables into the command line for scripts, rather than loading them into `process.env`.
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.
npm install dotenv --save
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
That's it.
process.env now has the keys and values you defined in your .env file.
var db = require('db')
db.connect({
host: process.env.DB_HOST,
username: process.env.DB_USER,
password: process.env.DB_PASS
})
If you are using iojs-v1.6.0 or later, 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/your/env/vars
Alias: load
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.
You can additionally, pass options to config.
Default: .env
You can specify a custom path if your file containing environment variables is named or located differently.
require('dotenv').config({path: '/custom/path/to/your/env/vars'})
Default: utf8
You may specify the encoding of your file containing environment variables using this option.
require('dotenv').config({encoding: 'base64'})
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.
var dotenv = require('dotenv')
var buf = new Buffer('BASIC=basic')
var config = dotenv.parse(buf) // will return an object
console.log(typeof config, config) // object { BASIC : 'basic' }
The parsing engine currently supports the following rules:
BASIC=basic becomes {BASIC: 'basic'}# are treated as commentsEMPTY= becomes {EMPTY: ''})SINGLE_QUOTE='quoted' becomes {SINGLE_QUOTE: "quoted"})MULTILINE="new\nline" becomes{MULTILINE: 'new
line'}
JSON={"foo": "bar"} becomes {JSON:"{\"foo\": \"bar\"}").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.
.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.
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 (var k in envConfig) {
process.env[k] = envConfig[k]
}
For dotenv@2.x.x: 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:
var dotenv = require('dotenv')
var variableExpansion = require('dotenv-expand')
const myEnv = dotenv.config()
variableExpansion(myEnv)
For dotenv@2.x.x: Use dotenv-expand.
For dotenv@1.x.x: We haven't been presented with a compelling use case for expanding variables and believe it leads to env vars that are not "fully orthogonal" as The Twelve-Factor App outlines.[1][2] Please open an issue if you have a compelling use case.
See CONTRIBUTING.md
See CHANGELOG.md
See LICENSE
Here's just a few of many repositories using dotenv:
Here's some projects that expand on dotenv. Check them out.
[4.0.0] - 2016-12-23
verbose option removed in favor of returning result.FAQs
Loads environment variables from .env file
The npm package dotenv receives a total of 40,449,474 weekly downloads. As such, dotenv popularity was classified as popular.
We found that dotenv demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
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