Multiconf

A lightweight and flexible configuration management library for Node.js applications. Multiconf simplifies working with JSON and JSONC configuration files, supporting both user-defined and default configurations with environment variable overrides.

Features

• 📁 Simple JSON/JSONC configuration management
• 🔄 Automatic fallback to default configurations
• 💬 JSONC support (JSON with comments)
• 🌍 Environment variable overrides
• 🚀 Lightweight and zero-dependencies

Installation

npm install multiconf

Quick Start

const Multiconf = require('multiconf');

// Initialize with default config directory (./conf)
const conf = Multiconf.get();

// Or specify a custom config directory
const conf = Multiconf.get('./config');

Configuration Structure

Multiconf supports two types of configuration files:

1. User Configurations (*.json or *.jsonc)
2. Default Configurations (*.json.default or *.jsonc.default)

The library will first look for user configurations, falling back to default configurations if not found.

Example Configuration Files

./conf/server.json.default:

{
  "hostname": "localhost",
  "port": 3141,
  "token": "<default-token>"
}

./conf/server.json:

{
  "hostname": "localhost",
  "port": 3141,
  "token": "QWERTY-123456"
}

Usage

// Access configuration values
console.log(`${conf.server.hostname}:${conf.server.port}`); // "localhost:3141"
console.log(`Token is ${conf.server.token}`); // "Token is QWERTY-123456"

JSONC Support

Multiconf supports JSONC (JSON with comments) format:

{
  // Server configuration
  "hostname": "localhost", // Server hostname
  "port": 3141,            // Server port
  "token": "QWERTY-123456" // Authentication token
}

Note: JSONC files have higher priority than JSON files. If both server.jsonc and server.json exist, server.jsonc will be used.

Environment Variables

Override configuration values using environment variables:

// Initialize with environment variable prefix
const conf = Multiconf.get('./conf', 'APP_CONF_');

Set environment variables to override configurations:

# Override server configuration
APP_CONF_server='{"token":"env-token-12345"}'

Environment variables must contain valid JSON strings that will be parsed and merged into your configuration.

License

MIT © 2017-2025 Volodymyr Sichka