for https://medium.com/@mohammedalrowad/painless-file-upload-using-feathersjs-services-e994e4734e0c

index.js

const myUpload = require('./my-upload');

const {
  authenticate
} = require('@feathersjs/authentication').express;
const multer = require('multer');

const storage = multer.diskStorage({
  destination: (req, file, cb) => cb(null, 'public/uploads'),
  filename: (req, file, cb) => cb(null, `${Date.now()}-${file.originalname}`)
});
const upload = multer({
  storage,
  limits: {
    fieldSize: 1e+8, // Max field value size in bytes, here it's 100MB
    fileSize: 1e+7 //  The max file size in bytes, here it's 10MB
    // files: the number of files
    // READ MORE https://www.npmjs.com/package/multer#limits
  }
});
// eslint-disable-next-line no-unused-vars
module.exports = function (app) {
  app.use('/media-upload', authenticate('jwt'), upload.array('files'), myUpload(app));
};