Extract first name from an array of email addresses.

index.js

const _ = require('lodash')
const fs = require('fs')
const json2csv = require('json2csv')

const emails = [
"firstname.lastname@test.be"
]
const mappedMails = _.compact(_.map(emails, email => {
  const firstName = _.capitalize(email.split('.')[0])
  if (firstName.indexOf('@') < 0) {
    return { "firstName": firstName, "email": email }
  }
}))

try {
  const csv = json2csv({ data: mappedMails, fields: [ 'firstName', 'email' ] })
  fs.writeFile('./emails.csv', csv, (err) => {
    if (err) throw err
    console.log('file saved')
  })
} catch (err) {
  console.error(err)
}