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const loadImage = function (image, onprogress) {
  if (onprogress === undefined) {
    onprogress = function () {}
  }
  return new Promise(function (resolve, reject) {
    var xhr = new window.XMLHttpRequest()
    var notifiedNotComputable = false

    xhr.open('GET', image, true)
    xhr.responseType = 'arraybuffer'

    xhr.onprogress = function (ev) {
      if (ev.lengthComputable) {
        onprogress(ev.loaded / ev.total * 100)
      } else {
        if (!notifiedNotComputable) {
          notifiedNotComputable = true
          onprogress(-1)
        }
      }
    }

    xhr.onloadend = function () {
      if (!xhr.status.toString().match(/^2/)) {
        reject(xhr)
      } else {
        if (!notifiedNotComputable) {
          onprogress(100)
        }
        resolve()
      }
    }

    xhr.send()
  })
}