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Small utility function that loads env file with the option to specify file path.
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README.md

minidotenv

Simple function that loads and parses .env file(s). env file is a text file where you specify environment variables that you want to use somewhere in your code.

You can attach the environment variables to Node's process.env object if specified. Do this at the beginning of your app.

This library has no runtime dependencies and provides Typescript definitions.

Usage

By default the function will attempt to load .env file from the location where code is being executed.

Example usage:

// .env
PORT=3000

// ./env.js
import minidotenv from 'minidotenv'

// Loads .env automatically from current folder
const config = minidotenv()

export default config


// ./app.js
import express from 'express'
import config from './env'

const app = express()
// [...]
app.listen(config('PORT'))

Specify custom location for env file:

import minidotenv from 'minidotenv'

const config = minidotenv({
  path: path.join(__dirname, 'config', '.env')
})

export default config

Automatically load all variables into Node process.env object:

// ./.env
FOO=BAR

// ./app.js
import minidotenv from 'minidotenv'

const config = minidotenv({ inject: true })
console.log(process.env.FOO) // BAR

FAQ

Q: Why should I use env file?

A: It's useful to configure your app via environment variables. You can put them at one place so the values don't have to be hard-coded and you can actually change them for different kinds of build. Lot of cloud providers enable to set environment variables in some way so you can have variables for production and local development. WARNING! Do not commit env file into version control as it might contain sensitive information (such as password for database etc).

Q: Do I have to call minidotenv() in every place where I need to retrieve the value?

A: No and actually it's not recommended. Everytime you call the function, the file is loaded from the disk. You should reference the function in your code via variable. Another solution is to call minidotenv() in separate file and then export the returned function. You can then use it anywhere. For complex projects, consider using Dependency injection so you always have the same function everywhere.

Q: This sucks! It does not work in the browser! Why?

A: Browsers do not have the concept of Node's process object so this will not work. This library will not overcome this obstacle. You should pass the environment variables during build time as global variables which you can then reference later in your code. Webpack supports this.

Q: Can I use this library to load environment variables when calling npm script in package.json?

A: No. Look at dotenv and dotenv-cli libraries.

Q: If I use 'inject' option, the numeric values from the env file are retrieved from 'process.env' object as strings. Why?

A: That is how the Node runtime works. Anything that is set to process.env object is converted to string eventually.

API

Package exposes single function as default. This function creates a closure where the contents of parsed env file are held. You can pass options to the function to customize behaviour (see below).

(options: { inject?: boolean, path?: string, env?: NodeJS.ProcessEnv, }) => (key: string) => string | number | undefined

This function returns another function which retrieves the values by key:

(key: string) => string | number | undefined

Options

  • inject: boolean: Injects the variables into process.env object by default or optionally to object passed via env option.
  • path: Path to your env file. By default it loads file called .env in the location of execution (ususally root of the project).
  • env: If you need to override process.env object when inject options is set to true. It should be Javascript object.

env file

This file is a simple text file. Name it .env and place it at the root of your project. Key and value is separated by =. Place each pair on new line. You can have values like this in it:

FOO=BAR
SENTENCE=is made of words
PORT=3000
SIZE=1.23
# Comment
VERSION=1.2.3

The values are coerced into strings if the value is not a number (integer or float). The parsing is very simple. IMPORTANT! If you add quotes to values they will not be stripped. This means using this: FOO="BAR" will result it key FOO having value '"BAR"' (includes the double quotes). Quotes are not neccessary in env file and removing them might cause some troubles (for example passwords including a quote).

Development

The project uses Typescript. There are several NPM scripts:

  • build: Builds the library into regular CommonJS module with bundled Typescript definitions (and source map).
  • test: Run unit tests.
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