multer s3 contentType fix

multerconfig.js

import stream from 'stream';
const mime = require('mime-types');

import aws from 'aws-sdk';
import multer from 'multer';
import multerS3 from 'multer-s3';

multer({
//...,
storage: multerS3({
  s3: aws.S3({
    accessKeyId: process.env.accessKeyId,
    secretAccessKey: process.env.secretAccessKey,
    region: process.env.region,
  }),
    contentType: (req: Express.Request, file: Express.Multer.File, cb: (error: any, mime?: string, stream?: NodeJS.ReadableStream) => void) => {
      const contentType = mime.lookup(file.originalname);
      file.stream.once('data', function (firstChunk) {
        var outStream = new stream.PassThrough();
        outStream.write(firstChunk);
        file.stream.pipe(outStream);

        cb(null, contentType, outStream);
      });
    },
    //...

    })
}