Dead simple configuration loader and parser for node deployments.

Usage no npm install needed!

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  import c11n from 'https://cdn.skypack.dev/c11n';


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c11n is a dead simple configuration loader and parser for node deployments.
It outputs an object that encapsulates unified configuration settings from environment variables, json files and command line arguments.


Let's consider we have an example.json file with the following content:

    "redis": { 
        "host": "redis.my-great-app.com",
        "port": 6379

    "facebook": {
        "id": 123456789,
        "key": "myfacebookapikey"

Drop a few lines into index.js:

const conf = require('c11n')

conf('./example', { prefix: 'my_app' })
    .then((config) => console.log(config))
    .catch((error) => console.error(error.stack || error))

Finally, expose settings to env and argv as well and run our app:

export my_app_domain=my-great-app.com
export my_app_redis_auth=foobar
export my_app_cookie_secret=foobar
export my_app_cookie_maxAge=365

node ./ --cookie_secret=barfoo --http_port=8080


  domain: 'my-great-app.com',
  redis: { 
    auth: 'foobar', 
    host: 'redis.my-great-app.com', 
    port: 6379 
  cookie: { 
    secret: 'barfoo', 
    maxage: 365 
  facebook: { 
    id: 123456789, 
    key: 'myfacebookapikey' 
  http: { port: 8080 } 


var c11n = require('c11n')

c11n([filePaths...], [options], [callback]) ⇒ Promise

options.prefix Include only those env variables which are starting with this prefix. Defaults to null.
options.dir Directory path to try to find and include NODE_ENV.json. Defaults to null.
options.dirs An array of directory paths. Each of them will be treated like options.dir.

Gather and merge configuration from env, additional .json files and argv in this order. c11n supports both error-first callback and Promise APIs.

Note If no file extension provided in a filePath then .json will be used.

c11n.load([filePaths...], [options], [callback]) ⇒ Promise

It's the module.exports of this package, same as the above-mentioned.

c11n.loadFromEnv([options]) ⇒ Object

options.prefix Include only those env variables which are starting with this prefix. Defaults to null.

Parse configuration from process.env and return result immediately.

c11n.loadFromFile(path, [options], [callback]) ⇒ Promise

Read and parse configuration from the file at given path. Please notice that, it's an async function.

c11n.loadFromArgv([options]) ⇒ Object

Parse configuration from process.argv and return result immediately. This function uses minimist internally for pre-parsing.

c11n.loadFromObject(object, [options]) ⇒ Object

Parse configuration from any given object and return result immediately. Used internally by other methods of this module.

This function iterates over keys of an object and breaks it into sub-objects along the '.'s and '_'s as separator characters. Leading and trailing separators are ignored, repeating separators are reduced to a single '_'.


const obj = {
    '__redis_port': 6379,
    'redis__host': 'localhost',
    'domain___': 'my-domain.com',
    'http.port': 8080,
    '_https...port': 8081



    redis: {
        port: 6379,
        host: 'localhost'
    domain: 'my-domain.com',
    http: { port: 8080 },
    https: { port: 8081 }

If a key has a value but there are nested settings for the same key, then the original value will be accessible under the special key: '_'.


const obj = {
   domain: 'example.com',
   cache: true,
   cache_ttl: 1209600,
   cache_size: '300mb'



   domain: 'example.com',
   cache: {
       _: true,
       ttl: 1209600,
       size: '300mb'


If set to false then resulting object will be mutable. Defaults to true. All the above-mentioned methods are accepting this option.


With npm:

npm install --save c11n

With git:

git clone git://github.com/schwarzkopfb/c11n.git
cd c11n
npm test


MIT license.