Unable to add attachment in AWS SES using SendRawEmail

I am using AWS SES service and I have followed AWS documentation https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-ses/classes/sendrawemailcommand.html for SES SendRawMail which provides a feature to add attachments with the email.

My code Implementation :

const { SESClient, SendRawEmailCommand } = require("@aws-sdk/client-ses");

const client = new SESClient({
    region : "us-east-1",
    credentials: {
      accessKeyId : "**************",
      secretAccessKey : "**************"
    }
});


var json = {
  "colors": [{
          "color": "black",
          "category": "hue",
          "type": "primary",
          "code": {
              "rgba": [255, 255, 255, 1],
              "hex": "#000"
          }
      }
  ]
};

var file = new Buffer(JSON.stringify(json)).toString("base64");

const payload = `From: *****@gmail.com
To: a**********@gmail.com
Subject: AWS SES Attachment
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="NextPart"
--NextPart
Content-Type: text/html; charset=us-ascii
This is the <b>body</b> of the email.
--NextPart
Content-Type: multipart/form-data;
Content-Disposition: attachment; filename="sample.txt"
Content-Transfer-Encoding: base64
${file}
--NextPart--`

const input = {
    "Destinations": ["********@gmail.com"],
    "FromArn": "",
    "RawMessage": {
      "Data": payload
    },
    "ReturnPathArn": "",
    "Source": "*********@gmail.com",
    "SourceArn": ""
  };
  const command = new SendRawEmailCommand(input);
  const response = client.send(command).then(res => res);

I am getting this error while working on my javascript application *

/node_modules/@aws-sdk/util-buffer-from/dist-cjs/index.js:6 const fromArrayBuffer = (input, offset = 0, length = input.byteLength - offset) => { ^

TypeError: Cannot read properties of undefined (reading 'byteLength') at fromArrayBuffer (/home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/util-buffer-from/dist-cjs/index.js:6:60) at Object.toBase64 [as base64Encoder] (/home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/util-base64/dist-cjs/toBase64.js:5:68) at se_RawMessage (/home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/client-ses/dist-cjs/protocols/Aws_query.js:4267:35) at se_SendRawEmailRequest (/home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/client-ses/dist-cjs/protocols/Aws_query.js:4661:31) at se_SendRawEmailCommand (/home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/client-ses/dist-cjs/protocols/Aws_query.js:546:12) at serialize (/home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/client-ses/dist-cjs/commands/SendRawEmailCommand.js:40:55) at /home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/middleware-serde/dist-cjs/serializerMiddleware.js:12:27 at /home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/middleware-endpoint/dist-cjs/endpointMiddleware.js:20:16 at async /home/cedcoss/anuj-work/research/ses-attached/node_modules/@aws-sdk/middleware-logger/dist-cjs/loggerMiddleware.js:7:26

Node.js v20.3.0 *