Unable to upload file using googleapis on Google Drive - node.js

Question

I have a problem with the file upload on google drive using the package googleapis (v.40):
In my web application (written in Vue js) i need to upload an image file of user 'A' into the google drive space of user 'B' using googleapis.
For this, i have created a "service-account" from the google console platform (of user B) and generated the credentials.json for the API access. (JWToken,service-to-service scenario)
In my web application, after getting the AccessToken by means the json credentials of the service account, i'm ready to upload the file. But, when i call the drive.files.create(...) api i get the following error:
Invalid multipart request with 0 mime parts.
Here some code:
...
// get google api
const {google} = require("googleapis");
const drive = google.drive("v3");
// get authorization token
let authToken = await getAuthToken() // it perfectly works
console.log(authToken)
let metadata = {
name: name,
parents: [idOfTheParentFolder]
}
let media = {
mimeType: 'image/jpeg',
body: file
}
let objImage = {
auth: authToken,
resource:metadata,
media: media,
fields: 'id',
}
drive.files.create(objImage, function (error, success) {
if (!error) {
...
}
else{
// here i got the error in question
}
})
I've tried exactly this code in a single node js file and it works fine, but it doesn't works in the web browser Vue application.
Let me say first that the API for showing the files (drive.files.list()) and the API for create a folder (drive.files.create()) they work just fine in my web application.
Any suggestion?