const fastify = require('fastify')()
const fastifyEnv = require('fastify-env')

const schema = {
  type: 'object',
  required: [ 'PORT' ],
  properties: {
    PORT: {
      type: 'string',
      default: 3000
    }
  }
}

const options = {
  confKey: 'config', // optional, default: 'config'
  schema: schema,
  data: data // optional, default: process.env
}

fastify
  .register(fastifyEnv, options)
  .ready((err) => {
    if (err) console.error(err)

    console.log(fastify.config) // or fastify[options.confKey]
    // output: { PORT: 3000 }
  })

const options = {
  dotenv: true // will read .env in root folder
}

// or, pass config options avalible on dotenv module
const options = {
  dotenv: {
    path: `${__dirname}/.env`,
    debug: true
  }
}