HTTPRequestCallbacks.js

const makeHTTPRequest = (url, methodType, callback) => {
  const xhr = new XMLHttpRequest()
  xhr.open(methodType, url, true)
  xhr.onreadystatechange = () => {
    if (xhr.readyState === 4 && xhr.status === 200) {
      callback(xhr.responseText)
    }
  }
  xhr.send()
}

const getLogin = (response) => {
  console.log(JSON.parse(response))
}

const url = 'https://api.github.com/users/maecapozzi'
makeHTTPRequest(url, 'GET', getLogin)