Send Email with Attachment File from Lambda (Nodejs)

import {
    S3Client,
    GetObjectCommand
  } from "@aws-sdk/client-s3";
  import { SESClient, SendRawEmailCommand } from "@aws-sdk/client-ses";
  import { Readable } from "stream";
  const s3Client = new S3Client({ region: "ap-southeast-2" });
  const sesClient = new SESClient({ region: "ap-southeast-2" });


  export const sendEmail = async () => {
    const senderEmail = process.env.SENDER_EMAIL_ADDRESS;
    const recipientEmail: any = process.env.RECIEVER_EMAIL_ADRESS;
    const subject = "SUBJECT here";
    const bodyText =
      "Hello,\r\n\nPlease see the attached csv file \n\nThanks";
  
    const getObjectCommand = new GetObjectCommand({
      Bucket: process.env.BUCKET,
      Key: process.env.BUCKET_KEY,
    });
  
    const attachmentData = await s3Client.send(getObjectCommand);
    const attachmentBuffer = await streamToBuffer(
      attachmentData.Body as Readable
    );
  
    const attachmentBase64 = attachmentBuffer.toString("base64");
  
    const emailData =
      `From: ${senderEmail}\r\n` +
      `To: ${recipientEmail}\r\n` +
      `Subject: ${subject}\r\n` +
      `MIME-Version: 1.0\r\n` +
      `Content-Type: multipart/mixed; boundary="boundary"\r\n\r\n` +
      `--boundary\r\n` +
      `Content-Type: text/plain; charset=utf-8\r\n` +
      `${bodyText}\r\n\r\n` +
      `--boundary\r\n` +
      `Content-Type: application/octet-stream\r\n` +
      `Content-Disposition: attachment; filename="file.csv"\r\n` +
      `Content-Transfer-Encoding: base64\r\n\r\n` +
      `${attachmentBase64}\r\n\r\n` +
      `--boundary--`;
  
    const sendRawEmailCommand = new SendRawEmailCommand({
      RawMessage: {
        Data: Buffer.from(emailData),
      },
      Source: senderEmail,
      Destinations: [recipientEmail],
    });
  
    const result = await sesClient.send(sendRawEmailCommand);
    return result.MessageId;
  }

  async function streamToBuffer(stream: Readable): Promise<Buffer> {
    return new Promise((resolve, reject) => {
      const chunks: Uint8Array[] = [];
      stream.on("data", (chunk) => chunks.push(chunk));
      stream.on("end", () => resolve(Buffer.concat(chunks)));
      stream.on("error", reject);
    });
  }