uploadFile.js

uploadFile () {
  // CSV File
  const csv = this.get("csv");
  
  // Data to pass to the server
  let data;
  
  // Option 1) Use FormData (preferred)
  data = new FormData();
  data.append("csv", csv, "csv");
  
  // Option 2) Pass a raw object
  data = {csv};
  
  // Option 3) Pass file directly
  data = csv;
  
  // 1st Transport Method (preferred)
  $.ajax({
      type: "POST",
      url: this.url(),
      data,
      success () {
          console.log("success");
      },
      error () {
          console.log("error");
      },
      xhrFields: {
          onprogress (progress) {
              console.log("progress", progress);
          }
      },
      processData: false,
      contentType: csv.type
  });
  
  // 2nd Transport Method, use backbone's built in
  this.save(data, {
      xhrFields: {
          onprogress (progress) {
              console.log("progress", progress);
          }
      },
      processData: false,
      contentType: csv.type
  });
  
  // 3rd Transport Method, XMLHttpRequest
  const xhr = new XMLHttpRequest();
  xhr.open("POST", this.url(), true);
  xhr.onload = () => {
      console.log("onload", xhr);
  };
  
  xhr.onerror = () => {
      console.log("err", xhr);
  };
  
  xhr.upload.onprogress = (event) => {
      console.log("progress", event, xhr);
  };
  
  xhr.setRequestHeader("Content-Type", csv.type);
  xhr.setRequestHeader("X-System", "fub-spa");
  xhr.send(data);
}