var formdata = new FormData()

formdata.append(

  'image',

  fileInput.files[0],

  'demo.png'

)

formdata.append('upscale', '4')

​

var requestOptions = {

  method: 'POST',

  body: formdata,

  redirect: 'follow',

}

​

fetch('http://127.0.0.1:8080/api/imageUpscaler/', requestOptions)

  .then((response) => response.text())

  .then((result) => console.log(result))

  .catch((error) => console.log('error', error))