MLHttpRequest: progress event handler

README.md

Usage with axios

const handler = HttpProgressHandler()

axios.get('/download?ID=12345', {
  onDownloadProgress: function (e) {
    const { speed, percent, completed } = handler(e)
    console.log(completed + 'MB (' + percent + '%) ' + speed + 'KB/s')
  }
})

HttpProgressHandler.js

export function HttpProgressHandler () {
  let lastNow = new Date().getTime()
  let lastKBytes = 0

  return function onHttpProgressHandler (e) {
    if (!e.lengthComputable) return

    const now = new Date().getTime()
    const bytes = e.loaded
    const total = e.total
    const percent = bytes / total * 100
    const kbytes = bytes / 1024
    const mbytes = kbytes / 1024
    const uploadedkBytes = kbytes - lastKBytes
    const elapsed = (now - lastNow) / 1000
    const kbps = elapsed ? uploadedkBytes / elapsed : 0

    lastKBytes = kbytes
    lastNow = now

    return {
      speed: kbps.toFixed(2),
      percent: percent.toFixed(2),
      completed: mbytes.toFixed(2)
    }
  }
}