What is env-var?
The env-var npm package is a utility for accessing and validating environment variables in Node.js applications. It provides a simple and consistent API for retrieving environment variables, ensuring they meet specified criteria, and handling default values.
What are env-var's main functionalities?
Accessing Environment Variables
This feature allows you to access environment variables and convert them to the desired type. In this example, the 'PORT' environment variable is retrieved and converted to a positive integer.
const env = require('env-var');
const port = env.get('PORT').asIntPositive();
console.log(`Server running on port: ${port}`);
Default Values
This feature allows you to specify default values for environment variables. If the 'HOST' environment variable is not set, it defaults to 'localhost'.
const env = require('env-var');
const host = env.get('HOST').default('localhost').asString();
console.log(`Server running on host: ${host}`);
Validation
This feature ensures that certain environment variables are set and meet specified criteria. In this example, the 'API_KEY' environment variable is required and must be a string.
const env = require('env-var');
const apiKey = env.get('API_KEY').required().asString();
console.log(`API Key: ${apiKey}`);
Custom Validators
This feature allows you to define custom validation logic for environment variables. In this example, the 'CUSTOM_VAR' environment variable must start with 'custom-'.
const env = require('env-var');
const customValidator = (value) => value.startsWith('custom-');
const customVar = env.get('CUSTOM_VAR').required().asString().validate(customValidator);
console.log(`Custom Var: ${customVar}`);
Other packages similar to env-var
dotenv
dotenv is a popular package for loading environment variables from a .env file into process.env. It does not provide validation or type conversion features like env-var, but it is widely used for managing environment variables in development.
joi
joi is a powerful schema description language and data validator for JavaScript. While it is not specifically designed for environment variables, it can be used to validate them. It offers more complex validation rules compared to env-var.
convict
convict is a configuration management tool for Node.js that allows you to define a schema for your configuration, including environment variables. It provides validation and default values, similar to env-var, but also supports nested configurations and different configuration sources.
env-var
- 🏋 Lightweight. Zero dependencies and just ~4.7kB when minified!
- 🧹 Clean and simple code, as shown here.
- 🚫 Fails fast if your environment is misconfigured.
- 👩💻 Friendly error messages and example values for better debugging experience.
- 🎉 TypeScript support provides compile time safety and better developer experience.
- 📦 Support for frontend projects, e.g in React, React Native, Angular, etc.
Contents
Install
npm
npm install env-var --save
yarn
yarn add env-var
Getting started
You can use env-var
in both JavaScript and TypeScript!
JavaScript example
const env = require('env-var');
const PASSWORD = env.get('DB_PASSWORD')
.required()
.convertFromBase64()
.asString();
const PORT = env.get('PORT').default('5432').asPortNumber()
TypeScript example
import { get } from 'env-var';
const PORT: number = get('PORT').required().asPortNumber();
For more examples refer to EXAMPLE.md and the /example
directory.
API
env-var
supports many accessor functions such as asFloatPositive()
, asJson()
and asRegExp()
. For a full list of env-var
API calls, check out API.md.
You can also create your own custom accessor; refer to the usingAccessor
section of API.md.
FAQ / Examples
- Integration with dotenv
- Logging
- React
- Next.js
- Vite
- Custom Accessors & Validation Logic
Contributing
Contributions are welcomed and discussed in CONTRIBUTING.md. If you would like to discuss an idea, open an issue or a PR with an initial implementation.
Contributors
- @aautio
- @avocadomaster
- @caccialdo
- @ChibiBlasphem
- @DigiPie
- @evanshortiss
- @gabrieloczkowski
- @hhravn
- @ineentho
- @itavy
- @jerome-fox
- @joh-klein
- @Lioness100
- @MikeyBurkman
- @pepakriz
- @rmblstrp
- @shawnmclean
- @todofixthis
- @xuo