Refactored a little bit your upload function.
const path = require("path");
const fs = require('fs');
const mime = require('mime-types'); //used to detect file's mime type
module.exports = async (imgPath) => {
// name of the file like image01.jpg
const name = path.basename(imgPath);
// read contents of file
const buffer = await fs.statSync(imgPath);
return strapi.plugins.upload.services.upload.upload({
data: {}, //mandatory declare the data(can be empty), otherwise it will give you an undefined error.
files: {
path: imgPath,
name: name,
type: mime.lookup(imgPath),
size: buffer.size,
},
});
};