Snippet for my Medium article

server.js

import Koa from 'koa'
import KoaRouter from 'koa-router'
import { asValue } from 'awilix'
import { scopePerRequest, makeInvoker } from 'awilix-koa'
import configureContainer from './configureContainer'

const app = new Koa()
const router = new KoaRouter()
const container = configureContainer()

// This installs a scoped container into our
// context - we will use this to register our current user!
app.use(scopePerRequest(container))
// Let's do that now!
app.use((ctx, next) => {
  ctx.state.container.registerValue({
    // Imagine some auth middleware somewhere...
    // This makes currentUser available to all services!
    currentUser: ctx.state.user
  })
  return next()
})

// Now our route handlers will be able to resolve a todos service..
// using DEPENDENCY INJECTION! YEEEEHAW!
// P.S: be a good dev and use multiple files. ;)
const todosAPI = ({ todosService }) => {
  return {
    getTodos: async (ctx) => {
      const todos = await todosService.getTodos(ctx.request.query)
      ctx.body = todos
      ctx.status = 200
    },
    createTodo: async (ctx) => {
      const todo = await todosService.createTodo(ctx.request.body)
      ctx.body = todo
      ctx.status = 201
    },
    updateTodo: async (ctx) => {
      const updated = await todosService.updateTodo(
        ctx.params.id,
        ctx.request.body
      )
      ctx.body = updated
      ctx.status = 200
    },
    deleteTodo: async (ctx) => {
      await todosService.deleteTodo(
        ctx.params.id,
        ctx.request.body
      )
      ctx.status = 204
    }
  }
}

// Awilix magic will run the above function
// every time a request comes in, so we have
// a set of scoped services per request.
const api = makeInvoker(todosAPI)
router.get('/todos', api('getTodos'))
router.post('/todos', api('createTodo'))
router.patch('/todos/:id', api('updateTodo'))
router.delete('/todos/:id', api('deleteTodo'))

app.use(router.routes())
app.listen(1337)