env

Read environment variables in a robust way and finally stop getting undefineds everywhere across your config.

npm install @fine-js/env

Basic Usage

const env = require('@fine-js/env')

env.has('PORT') // => false
env.get('PORT') // => Error: env var "PORT" missing
env.get('PORT', {required: false, defaultsTo: 3000, parseFn: Number}) // => 3000

console.log(env) // Prints a nice represantation sorted alphabetically by key

API

get(name, options)

Returns the value of variable name or throws an Error based on following options:

• required bool [true]

  When true, throw in case env var is not set.

• defaultsTo anything [undefined]

  For non-required env vars, this value will be returned directly without parsing with parseFn.

• parseFn function [(x) => x]

  Values that come from process.env will be passed to this function for parsing, e.g. for port numbers, you'd want Number; feel free to do any validations here, but note that defaultsTo is returned directly.

• allowEmpty bool [false]

  By default, empty strings on process.env throw an error; note that setting defaultsTo to '' is okay.

• allowUndefined bool [false]

  Whether resulting value can be undefined.

• allowNull bool [false]

  Whether resulting value can be null.

has(name)

Returns true when the variable named name is set to any value.

createEnv()

Default export is an environment object based with the contents of process.env at the time of the module being required. You can get an updated version or create new environment from any other object:

const {createEnv} = require('@fine-js/env')

// Defaults to using process.env at the moment of calling.
createEnv()

// Or you can pass any other object.
createEnv({
  my: 'custom',
  env: '42',
})

Changes

1.0.0

I had no need to change this package for years now, seems like it's time for the first stable version with tests, overhauled API and 0 dependencies 🎉

Env is no longer a class, but a plain object with 4 exports:

• get is a main function for reading env
• has will tell you if environment has a certain key
• keys creates an iterator for all the environment variable names present
• createEnv allows to create a new environment

Not being a class means no longer inherting from Map, which makes it non-iterable except via keys() (there is rarely a need to iterate over values). Another bonus is being nicely printable with console methods and serializable to JSON.

oneOf option is removed as being out of scope. You'll get better validations and more options by putting those kinds of things under parseFn.

env.get('PORT', {
  required: false,
  defaultsTo: 3000,
  parseFn: (val) => {
    const port = Number(val)
    assert(Number.isSafeInteger(port) && port >= 0 && port <= 65535)
    return port
  }
})

0.0.2

Fixed

• Small codebase issues and typos.

0.0.1

Added

• Initial realease.