Getting started with dotenv and .env files

Getting started with dotenv and .env files

What are dotenv and .env?

.env is a dotfile which developers can use to store environment variables for use in various code projects. It is beneficial to learn more about the specifics of and the format of a .env file, as environment variables are rather common in software development. The basic syntax for environment variables within a .env file is simply KEY=value . Check the parser rules below for a more detailed explanation.

dotenv is an npm package that simplifies usage of .env files.

Select the right tool for the job. Using Webpack? There's a package for that!

How to use dotenv

Installing it as a dependency

npm

npm install --save dotenv

yarn

yarn add dotenv

Including it in a JavaScript source file

Without path to .env

require("dotenv").config();

With path to .env

require("dotenv").config({path: './.env'});

Referencing environment variables

// When .env contains : ENV_NAME=Figment

const name = process.env.ENV_NAME;
console.log(`The ${name} community rocks!`); // The Figment community rocks!

dotenv parser rules

• Empty lines are skipped

• Lines beginning with # (comments) are ignored by the parser

• BASIC=basic becomes {BASIC: 'basic'}

• Empty values become empty strings - EMPTY= becomes {EMPTY: ''}

• Inner quotes are maintained - JSON={"foo": "bar"} becomes {JSON:"{\"foo\": \"bar\"}"

• Surrounding whitespace is removed from unquoted values (FOO= some_value becomes {FOO: 'some_value'} )

• Single and double quoted values maintain surrounding whitespace - FOO=" some_value " becomes {FOO: ' some_value '}

• Double quoted values expand escaped newlines - MULTILINE="new\nline" becomes

{MULTILINE: 'new
line'}

.gitignore the .env

Read more about ignoring files in git on the GitHub documentation.

Ignore files are used in many different Open Source repositories. Since we are working with blockchains and cryptocurrency, it is imperative to point out the security implications of this method. This prevents git from checking in the .env file to a public repository. If you are using a different code versioning system, there will be different requirements.

Create a file named .gitignore in the same directory as the project package.json and explicitly name the .env file on a line by itself within that .gitignore file.

.gitignore

.env

This is an important step to safeguarding any API keys, seed phrases or other sensitive information placed inside a .env file from being inadvertently sent to a public code repository on the internet, where they would immediately become vulnerable with a high likelihood of being scraped by bots.