Script de sorteio inimigo/amigo oculto

index.js

const { shuffle, map } = require('lodash')
const { sendMessages } = require('./send-email')

const input = shuffle(require('./input.json'))

function assign (array) {
  return map(array, (person, index, array) => {
    const friend = array[index + 1] || array[0]
    return {
      person,
      friend
    }
  })
}

sendMessages(assign(input))
  .then(result => {
    console.log(result)
  })
  .catch(err => {
    console.error(err)
  })

input.json

[{
  "name": "Fulano 01",
  "email": "email@mail.com"
}, {
  "name": "Fulano 02",
  "email": "email@hotmail.com"
}]

send-mail.js

const mailgun = require('mailgun-js')
const DOMAIN = '<--->'
const mg = mailgun({ apiKey: '<--->', domain: DOMAIN })

const buildMessageData = drawData => {
  const { person, friend } = drawData

  return {
    from: 'MailBô <postmaster@--->',
    to: person.email,
    subject: 'Inimigo Secreto - 2019',
    text: `Olá! ${person.name}, seu inimigo oculto é ${friend.name}`,
    html: `
    Olá! <b>${person.name}</b> seu inimigo oculto é <b>${friend.name}</b>`
  }
}

const sendMessages = data => {
  const messages = data.map(buildMessageData)
  const promises = messages.map(data => {
    return mg.messages().send(data)
  })

  return Promise.all(promises)
}

module.exports = { sendMessages }