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.

TOC

• mh-config
• TOC
• Introduction
  • Key features
  • Comparison
• Installation
• Usage
  • Usage-1: Include it in your module/code
  • Usage-2 Without modifying your code
• The config file
• Options
• Rules
• License

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

License

It's an MIT license; feel free to use as you will.