gistfile1.txt

'use strict';
const multer = require('multer');

const MIME_TYPE_MAP = {
  'image/png': 'png',
  'image/jpeg': 'jpg',
  'image/jpg': 'jpg'
};

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    let error = null;
    const isValid = MIME_TYPE_MAP[file.mimetype];
    if (!isValid) {
      error = new Error('Invalid mime type');
    }
    cb(error, 'images');
  },
  filename: (req, file, cb) => {
    const name = file.originalname
      .toLowerCase()
      .split(' ')
      .join('-');
    const ext = MIME_TYPE_MAP[file.mimetype];
    cb(null, name + '-' + Date.now() + '.' + ext);
  }
});

module.exports = multer({ storage: storage }).single('image');