config-decorators

Config Decorators

This is a configuration helper library that enables the efficient management of default dev settings and prod settings from environment variables. Useful for separating dev and prod environments, dockerization, etc.

Install

npm i config-decorators -S

Usage

• Create a class with the config props
  • Use inline settings for default values
  • Use the ENV decorator to define overrides if the ENV variable is available
• Instantiate the class with the loadConfig call
  • You CAN instantiate the same class more than once
  • You CAN create several classes with various decorators

Aaand... Done!

Config class

import { loadConfig, ENV } from './config-decorators';

export class Config {
	@ENV('MONGO_URL')
	mongoUrl = 'mongodb://localhost/test2';

	// Use it with a transform function
	@ENV('SERVER_PORT', parseInt)
	port = 8080;
}

export const config = loadConfig(Config);

Import

import * as mongoose from 'mongoose';
import { config } from './config';

mongoose.connect(config.mongoUrl);

How does it work?

The main stuff is at loadConfig:

• First, it instantiates your class
• Then it checks each prop having ENV decorators
  • If there's no ENV variable with the given name then steps to next prop
  • If there's a given transformator then the ENV variable is transformed
  • Overrides the value of the prop

Tests

• Clone the repo
• npm i
• npm run build -- You should have tsc (TypeScript) in your PATH
• npm run test

Tested on Node.js with TypeScript (2.1.4+) classes, ES6 build.

Further Dev Plans -- NOT READY YET

Create an issue if you need something.

Validation

	@ENV('SERVER_PORT', parseInt)
	@Validate(value => value > 1000)
	port = 8080;

CLI Parse

	@ENV('SERVER_PORT', parseInt)
	@CLI('port') // or something like this to parse `node app.js --port 8081`
	port = 8080;