A better way to retrieve environment variables


111.3.03 years ago4 years agoMinified + gzip package size for @mondora/env in KB


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A better way to retrieve environment variables in nodejs.


  • set defaults for environment variables
  • set defaults for environment variables only when NODE_ENV != production
  • throw an error if a required environment variable is not set
  • parse environment variables before returning them (eg, parse a base64 string into a Buffer)
  • get environment variables from a different source than process.env
  • for TypeScript, get the correct type information for the variable


yarn add @mondora/env


import env from "@mondora/env";

export const REQUIRED = env("REQUIRED", { required: true });
  required: true,
  nonProductionDefault: "DEFAULT"
export const NON_REQUIRED = env("NON_REQUIRED");
export const WITH_DEFAULT = env("WITH_DEFAULT", { default: "DEFAULT" });
// PARSED is a Buffer
export const PARSED = env("TO_BE_PARSED", {
  required: true,
  parse: value => Buffer.from(value)


env(name, options)

Retrieves the specified environment variable.

  • name string required: name of the environment variable to retrieve
  • options object:
    • required boolean: marks the variable as required. Ie, if the variable is not set, an error is thrown
    • nonProductionDefault boolean: makes a required variable only required when NODE_ENV == production, while giving it a default value otherwise
    • default string: a default value for the variable if it's not set
    • parse function: a function to transform the value of the variable (a string) into whatever before it's returned by env. The function is called only when a value or a default value for the variable was set

The value of the environment variable, parsed by the options.parse function if specified.


Sets the input source from which environment variables are retrieved (the default input source is process.env).

  • inputSource (string, string) map required: custom input source



To get started developing the library, clone the project and install dependencies with yarn. Then you can either:

  • yarn test: runs tests
  • yarn test --watch: runs tests, re-runs them on code changes
  • yarn coverage: runs tests, measures code coverage
  • yarn lint: runs code linters (prettier + tslint)
  • yarn prettify: formats code with prettier
  • yarn compile: compiles the project

NOTE: this project uses prettier to enforce code formatting. Installing the prettier extension for your editor of choice is highly recommended.


  • Run npm version x.x.x to bump a new version of the package. The command will set the specified version number in package.json, commit the change, tag the commit with vx.x.x

  • Push the commit and the tag to github: git push --tags origin master

  • If linting and automated tests pass, the module will automatically be published to npm

Note: you can use convenience commands npm version major, npm version minor, npm version patch to bump the consecutive major / minor / patch version of the package.

If you find any bugs or have a feature request, please open an issue on github!

The npm package download data comes from npm's download counts api and package details come from npms.io.