Config loader

Usage no npm install needed!

<script type="module">
  import anyCfg from '';



Build Status


Read program options from config files, environment variables and command line arguments.


const {config} = require('any-cfg')

const cfg = config({
  configDir: '.',
  configFile: '.myapprc',
  envPrefix: 'MYAPP_',
  HOST: {type: 'string', short: 'h'},
  PORT: {type: 'number', short: 'p', required: true},
  DEBUG: {type: 'boolean'},
  HELP: {type: 'boolean'},

const {
  HOST = 'localhost',
} = cfg.parse()

if (HELP) {

server.listen(PORT, HOST)

Detailed usage

Specify options using format FOO_BAR (upper snake case). Each option can have type, required flag and short name. Supported types are: string, number, boolean, list (array of strings) and map (object of strings).

First, options will be read from config files starting from configDir and going upwards. First file with basename configFile will be parsed. It must include an extension (either .json or .toml). Parser expects options to be formatted as foo_bar (lower snake case).

Then, options can be overwritten by environment variables. Upper snake case format with optional envPrefix is expected. Lists and maps are reset, not appended. Format for lists is comma or semicolon separated string. For maps it's a list of key-value pairs separated by =.

Lastly, options can be overwritten by command line arguments. The format is --foo-bar (lower kebab case) or -x for short options. Short options can be grouped (-abc). Boolean options should be either --opt for true and --no-opt for false. To provide a list, specify the same option multiple times. For map specify a list of key-value pairs separated by =. Special _ option is automatically added, which contains a list of the rest of command line arguments.


  • Load config from env vars
  • Load config from command line args
  • Load config from JSON files
  • Generate help message
  • 1.0