CODE EXAMPLE FOR TYPESCRIPT

multer s3 file upload

import 'dotenv/config.js'
import { MulterModule, FileFieldsInterceptor, FilesInterceptor, FileInterceptor } from '@nestjs/platform-express'
import { mimeTypeSupport } from '@helpers/helper.mimeType'
import aws from 'aws-sdk'
import { Request } from 'express'
import multer from 'multer'
import multerS3 from 'multer-s3'
import fs from 'fs'

aws.config.update({
	accessKeyId: process.env.AWS_ACCESS_KEY_ID,
	secretAccessKey: process.env.AWS_ACCESS_KEY
})

export class Multer {
	private static acl: String = 'ACL'

	static awsStorage: multer.StorageEngine = multerS3({
		s3: new aws.S3({
			credentials: new aws.Credentials({
				accessKeyId: process.env.AWS_ACCESS_KEY_ID,
				secretAccessKey: process.env.AWS_ACCESS_KEY
			}),
			hostPrefixEnabled: true,
			computeChecksums: true,
			correctClockSkew: true
		}),
		bucket: process.env.AWS_BUCKET_NAME,
		contentType: multerS3.AUTO_CONTENT_TYPE,
		serverSideEncryption: 'AES256',
		[Multer.acl as any]: 'public-read',
		metadata(_req: Request, file: Express.Multer.File, done: any) {
			if (!file) done(new Error('Get file upload failed'), null)
			done(null, file)
		},
		key(_req: Request, file: Express.Multer.File, done: any) {
			done(null, `${Date.now()}.${file.originalname.split('.')[1]}`)
		}
	})

	static fileFilter(_req: Request, file: Express.Multer.File, done: any) {
		if (!mimeTypeSupport(file.mimetype)) throw new TypeError('mimetype not supported')
		if (file.size >= 5242880) throw new TypeError('maximum file or image size must be 5 MB or under 5 MB')

		const fileName: string = `${Date.now()}.${file.originalname.split('.')[1]}`
		done(null, fileName)
	}
}