I’m using the @aws-sdk/client-s3 npm package to upload and download files to and from my AWS S3 Bucket. The app still works fine and uploads and downloads as expected but I get the following error on my console when I attempt to download a file.

(node:8400) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [TLSSocket]. Use emitter.setMaxListeners() to increase limit
(Use `node --trace-warnings ...` to show where the warning was created)

The app still works fine, but I’m worried about the memory leaks and suspect it’s coming from the @aws-sdk/client-s3 package. If you have fixed this issue please advice on how to take care of the memory leaks.

Here is my code for the s3service

s3Service.js

const {
  S3Client,
  PutObjectCommand,
  GetObjectCommand,
} = require("@aws-sdk/client-s3");

exports.s3Upload = async (file, fileKey) => {
  const s3client = new S3Client();

  const param = {
    Bucket: process.env.AWS_BUCKET_NAME,
    Key: fileKey,
    Body: file.buffer,
  };

  return s3client.send(new PutObjectCommand(param));
};

exports.s3DownloadFile = async (fileKey) => {
  const s3client = new S3Client({ region: process.env.AWS_REGION });

  const param = {
    Bucket: process.env.AWS_BUCKET_NAME,
    Key: fileKey,
  };

  try {
    return await s3client.send(new GetObjectCommand(param));
  } catch (error) {
    console.error("Error", error);
  }
};

and here’s my route code

/** Import statements */
const express = require("express");

const { s3DownloadFile } = require("../s3Service");
const { Company } = require("../models/companies");
const { Backup } = require("../models/backups");

const router = express.Router();

router.get("/download/:companyName/latest", async (req, res) => {
  try {
    const company = await Company.findOne({
      where: {
        companyName: req.params.companyName,
      },
    });

    if (!company)
      return res.status(404).send("The specified company does not exist");

    const backups = await Backup.findAll({
      where: {
        companyID: company.dataValues.companyID,
      },
      order: [["createdAt", "DESC"]],
    });

    if (backups.length === 0)
      return res.status(404).send("There are no backups for this company");

    let fileKey = `${company.companyID}/${backups[0].dataValues.fileName}`;
    const data = await s3DownloadFile(fileKey);

    // Set appropriate headers for the file download
    res.attachment(fileKey);

    data.Body.pipe(res);
  } catch (error) {
    res.status(500).send(error.message);
  }
});

module.exports = router;