Mh-config NPM | npm.io

mh-config

mh-config is a zero-dependency module that helps provide configuration to your existing or new applications in no time.

Storing configuration separate from code (not hard-coding) is based on The Twelve-Factor App methodology.

Introduction

Key features

Specify configuration in any file format: ini/json/js
Provide these configurations either via a config object or simply process environment variables
No need to edit your application's code, if you'd like it that way
Hot reload the config file without restarting or reloading your application

Comparison

How mh-config is different (& hopefully better) from the dotenv module?

mh-config accepts a number of files formats such as: ini/json/js
- So you don't need to change the format of your existing config file
- Using a '.js' file provide eve more flexibility; you can dynamically create configuration values using javascript e.g. modifying time as per day light saving
mh-config can be configured to hot reload the config file while your application is still running. This mean no downtime for your app!
- This also provides the ability to modify the process environment variables available to your application on the fly

Installation

# with npm
npm install mh-config

# or with Yarn
yarn add mh-config

Usage

Two usages are possible: 1. Usage-1: Include it in your application's code 2. Usage-2: Use without modifying your application's code

Usage-1: Include it in your module/code

const config = require('mh-config')({debug:true}); 
// pass in options like debug = true

if (config.error) {
  throw config.error
}

// assuming a file named config.ini exists with username=notadmin, then

// USE either of the following:
process.env['username']
// OR
config['username']

Usage-2 Without modifying your code

node -r mh-config/do <yourApp.js> config_option_debug=true
      # additional config options ^^^^^^^^^^^^^^^^^^^^^^^^

// yourApp.js

// USE either of the following:
process.env['username']
// OR
config['username']

The config file

By default, mh-config looks for a suitable file in the current working directory (cwd), usually the root of the project. A suitable file is one of the following formats:

.ini
.json
.js

Examples:

; config.ini
username=trump
password="2020"
port=1880

// config.json
{
    "username": "trump",
    "password": "2020",
    "port": 1880
}

// config.js
module.exports = {
    "username": "trump",
    "password": "2020",
    "port": 1880
}

Options

mg-config takes in config in two ways: 1. For Usage-1: via an object 2. For Usage-2: via command line arguments

name (for usage-1)	name (for usage-2)	description	accepted values	default
filename	config_option_filename	the filename (/with path) where config exists. Should be relative to the CWD		''
setEnv	config_option_setEnv	whether to set process's environment variable as well	true/false	true
overwriteExistingEnv	config_option_overwriteExistingEnv	whether to overwrite an existing environment variable	true/false	false
watchIntervalMs	config_option_watchIntervalMs	hot reload any changes to the config file every n milliSeconds		5000
debug	config_option_debug	whether to print debug messages on console	true/false	false

Rules

Each config values is converted into number if possible, unless surrounded by double/single quotes
If filename is not provided, mh-config looks for these file names in CWD and stops looking if it finds one:
- config.ini
- config.json
- config.js
mh-config will never mess with your existing process.env unless you specifically ask it to by setting 'overwriteExistingEnv = true'
Double and Single quotes are useful to mark a value as text e.g. "100" will be treated as a string while 100 as a number. This is only applicable for .ini files and command line arguments with -r option