@specialminds/configr

A small library to help you write better config files. Uses reflect-metadata to read, write, and validate JSON config files based on classes.

This is not the same as the configr package in npm. Just a happy coincidence.

Installation

Add the package @specialminds/configr to your project.

Yarn: yarn add @specialminds/configr NPM: npm i --save @specialminds/configr

We use semantic versioning, so be prepared for breaking API changes up to 1.0.0. We expect the worst will be naming of functions, but cannot guarantee it.

Usage

Configr bases itself on configurations defined as TypeScript classes. Decorate the properties you want to read/write to JSON config files, and let Configr handle the rest.

Example:

import { Configr } from '@specialminds/configr';

class MyConfigurationClass {
  @Prop({
    default: 8080,
  })
  serverPort!: number;

  @Prop({
    required: true,
  })
  tokenSecret!: string;
}

const betterConfig = new Configr(MyConfigurationClass);

// Parse from an object you've already got.
// Will throw because you're missing 'tokenSecret'.
betterConfig.parseJson({
  serverPort: 9191,
});

// Read a config file from disk. This call optionally takes any constructor
// parameters that your configuration class may require.
const cfg = betterConfig.readFromFileSync('./config.json');

console.debug(cfg.serverPort);

cfg.serverPort = 10001;

betterConfig.writeToFileSync(cfg, '/config.json');

Final thoughts

The library is a first implementation and there's a lot of room to grow. However, we want to keep the project relatively lean, a statically typed and easy-to-use way to manage configurations for your applications.

Future ideas ("roadmap")

• Full testing suite.
• Read/write to file directly on the augmented config object.
• Support for nested objects.
• ~~Asynchronous methods.~~
• Additional features on decorators (validators, parsers, transformers, proper support for full objects in structure).
• Improvements to documentation
• ???