promise-all.js

const asyncFn = (email) => {
  return new Promise((resolve, reject) => {
    $.get('//idnes.cz/' + email, (err, result) => {
      if (err) {
        return resolve({
          status: 'fail',
          email: email,
        })
      }
      
      return resolve({
          status: 'ok',
          email: email,
        })
    })
  })
}

const promises = [{email: 'vojta.tranta@gmail.com'}, {email: 'duro@avocode.com'}].map(email => {
  return asyncFn(email.email)
})

Promise.all(promises).then((results) => {
  results[0] // ---  {email: vojta.tranta@gmail.com, status: 'ok' } 
  results[1] // ---  {email: vojta.tranta@gmail.com, status: 'ok' }
})