Koach

A piecewise API framework for Node.js

Declarative React-like component model meets Koa middleware function composition 😱

Contributing

This project is still young and actively developed. If you want to show some ❤️, feel free to submit GitHub issues and pull requests!

Motivation and Design

Koach provides a powerful component model and a declarative way to express those components and their composition. It is an attempt to formalize many of the conventions and patterns common in Node middlewares. The foundational building blocks are Koa-style middleware functions.

A good component model enables composition. With Koach, a monolithic API can instead be expressed as a hierarchical composition of components and subcomponents. A carefully composed API makes it easy to break off independent pieces into their own dedicated microservices (I.e. separate repo, deployment, etc.) when the time is right.

Installation

$ yarn add koach
or
$ npm i koach

Usage

The simplest way to get started with Koach

import Koach, { Component, Router } from 'koach'

class App extends Component {
  compose() {
    return Router.spec()
      .get('/', ctx => ctx.body = 'Hello World!')
  }
}

// register our shiny new App component
Koach.registerComponent('App', () => App)

// listen on port 3000
Koach.listen(3000)

Getting Started

Koach in a nutshell:

• Define components by overriding compose(), returning either:
  • a Koa-style middleware function
  • a component specification
• Create a component specification with spec = Component.spec(config:Object) => Specification
  • Specify subcomponents with chainable use() statements spec.use(...subcomponents:Specification|Function) => Specification
• Configuration properties are available to your component as this.config
  • this.config can be treated as an Object or a function
    • Ex. this.config.auth.secret or this.config('auth.secret')
• Subcomponents are available to your compose() implementation as this.config.subcomponents

  compose() {
    return Router.spec()
      .use(this.config.subcomponents)
      .get('/status', ctx => ctx.body = 'Healthy')
  }

Documentation

Visit the Wiki for detailed documentation and steps to get started with Koach.

License

MIT