node_modules/avvio/examples/example.js

'use strict'

const avvio = require('..')()

function a (instance, opts, cb) {
  (opts.use || []).forEach(_ => { instance.use(_, { use: opts.subUse || [] }) })
  setTimeout(cb, 10)
}
const pointer = a

function b (instance, opts, cb) {
  (opts.use || []).forEach(_ => { instance.use(_, { use: opts.subUse || [] }) })
  setTimeout(cb, 20)
}

function c (instance, opts, cb) {
  (opts.use || []).forEach(_ => { instance.use(_, { use: opts.subUse || [] }) })
  setTimeout(cb, 30)
}

avvio
  .use(first, { hello: 'world' })
  .use(duplicate, { count: 0 })
  .use(function a (instance, opts, cb) {
    instance.use(pointer, { use: [b], subUse: [c] })
      .use(b)
    setTimeout(cb, 42)
  })
  .after(function (err, cb) {
    if (err) {
      console.log('something bad happened')
      console.log(err)
    }
    console.log('after first and second')
    cb()
  })
  .use(duplicate, { count: 4 })
  .use(third)
  .ready(function (err) {
    if (err) {
      throw err
    }
    console.log('application booted!')
  })

avvio.on('preReady', () => {
  console.log(avvio.prettyPrint())
})

function first (instance, opts, cb) {
  console.log('first loaded', opts)
  instance.use(second)
  setTimeout(cb, 42)
}

function second (instance, opts, cb) {
  console.log('second loaded')
  process.nextTick(cb)
}

function third (instance, opts, cb) {
  console.log('third loaded')
  cb()
}

function duplicate (instance, opts, cb) {
  console.log('duplicate loaded', opts.count)
  if (opts.count > 0) {
    instance.use(duplicate, { count: opts.count - 1 })
  }
  setTimeout(cb, 20)
}